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Showing papers on "Microstrip published in 2022"


Journal ArticleDOI
TL;DR: In this paper , the authors provide an overview of recent techniques and technologies investigated in the literature, to implement high performance on-chip antennas for millimeter-wave (mmWave) and terahertz (THz) integrated-circuit (IC) applications.
Abstract: Antennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside electronic devices. Although on-chip antennas have a limited range, they are suitable for cell phones, tablet computers, headsets, global positioning system (GPS) devices, and WiFi and WLAN routers. Typically, on-chip antennas are handicapped by narrow bandwidth (less than 10%) and low radiation efficiency. This survey provides an overview of recent techniques and technologies investigated in the literature, to implement high performance on-chip antennas for millimeter-waves (mmWave) and terahertz (THz) integrated-circuit (IC) applications. The technologies discussed here include metamaterial (MTM), metasurface (MTS), and substrate integrated waveguides (SIW). The antenna designs described here are implemented on various substrate layers such as Silicon, Graphene, Polyimide, and GaAs to facilitate integration on ICs. Some of the antennas described here employ innovative excitation mechanisms, for example comprising open-circuited microstrip-line that is electromagnetically coupled to radiating elements through narrow dielectric slots. This excitation mechanism is shown to suppress surface wave propagation and reduce substrate loss. Other techniques described like SIW are shown to significantly attenuate surface waves and minimise loss. Radiation elements based on the MTM and MTS inspired technologies are shown to extend the effective aperture of the antenna without compromising the antenna’s form factor. Moreover, the on-chip antennas designed using the above technologies exhibit significantly improved impedance match, bandwidth, gain and radiation efficiency compared to previously used technologies. These features make such antennas a prime candidate for mmWave and THz on-chip integration. This review provides a thorough reference source for specialist antenna designers.

62 citations


Journal ArticleDOI
TL;DR: In this article , 5.5 wt% TiO2 (MAS-T5.5) was used to adjust τf of MAS to −2.8 ppm/℃ whilst retaining low εr (5.24) and good Q×f (33,400 GHz), properties consistent with those obtained by infrared reflectance.
Abstract: 5G and forthcoming 6G communication systems require dielectric ceramics with low relative permittivity (εr) and near-zero temperature coefficient of resonant frequency (τf) for the lower part of the microwave (MW) band and at sub-Terahertz. Mg2Al4Si5O18 (MAS) ceramics are promising candidates due to their low εr (~ 6) and high-quality factor (Q×f > 40,000 GHz) but have a large τf. In this study, 5.5 wt% TiO2 (MAS-T5.5) was used to adjust τf of MAS to −2.8 ppm/℃ whilst retaining low εr (5.24) and good Q×f (33,400 GHz), properties consistent with those obtained by infrared reflectance. A demonstrator microstrip patch antenna with gain 4.92 dBi and 76.3% efficiency was fabricated from MAS-T5.5.

53 citations


Journal ArticleDOI
TL;DR: In this paper , a novel coding metasurface based on low Q resonators and fast optimization method is proposed to achieve wideband radar cross section (RCS) reduction of the microstrip antenna array (MAA) while maintaining its radiation properties.
Abstract: In this letter, a novel coding metasurface (CM) based on low Q resonators and fast optimization method is proposed to achieve wideband radar cross section (RCS) reduction of the microstrip antenna array (MAA) while maintaining its radiation properties. Theoretical analysis reveals the relationship between the Q value and the phase shift of the resonator, which indicates that the wideband control of the reflected wave can be achieved with the low Q resonator. Moreover, the fast optimization method based on the convolution theorem is proposed, which enhances the optimization efficiency of the coding matrix. Finally, the CM with two kinds of low Q resonators is constructed and applied to the MAA for wideband RCS reduction. The measured results indicate that the proposed low RCS MAA (LRMAA) can realize more than 10 dB RCS reduction in 5.8–21.5 GHz, which also demonstrates superior specular scattering suppression. In parallel, the radiation properties of the LRMAA are consistent with those of MAA. The proposed strategy achieves the high integration of radiation and scattering properties, which has potential applications in antenna systems of stealth platforms.

39 citations


Journal ArticleDOI
TL;DR: In this paper , a simple and effective approach to achieve frequency tunability is proposed by the switching mechanism of the two PIN diodes, which achieves a multiband response with the four frequency tunable bands along with a minimum reflectance response of −28.22 dB.
Abstract: The proposed work represents a simple and effective approach to achieve frequency tunability. The tunability is attained by the switching mechanism of the two PIN diodes. The biasing issue is reduced due to the usage of two PIN diodes. Simulation is carried by a high‐frequency structure simulator tool and compared with the fabricated structure for the authentication. Antenna fabrication is performed by low‐profile material FR‐4. Three modes were analyzed and compared in terms of resonating frequency, reflectance response, gain, bandwidth, and electric field based upon switching of PIN diodes. The proposed antenna structure provides a multiband response with the four frequency tunable bands along with maximum frequency tunability of 700 MHz and a minimum reflectance response of −28.22 dB. The proposed structure opens a new door of applications like satellite communication, military, and a sensor for the S, C, X, and Ku bands. The presented design was also compared with the previously published papers to identify the improvement.

39 citations


Journal ArticleDOI
TL;DR: In this paper , a dual-polarized highly folded self-grounded Bowtie antenna that is excited through I-shaped slots is proposed for applications in sub-6 GHz 5G MIMO antenna systems.
Abstract: In this communication, a novel dual-polarized highly folded self-grounded Bowtie antenna that is excited through I-shaped slots is proposed for applications in sub-6 GHz 5G multiple-input-multiple-output (MIMO) antenna systems. The antenna consists of two pairs of folded radiation petals whose base is embedded in a double layer of FR-4 substrate with a common ground-plane which is sandwiched between the two substrate layers. The ground-plane is defected with two I-shaped slots located under the radiation elements. Each pair of radiation elements are excited through a microstrip line on the top layer with RF signal that is 180° out of phase with respect to each other. The RF signal is coupled to the pair of feedlines on the top layer through the I-shaped slots from the two microstrip feedlines on the underside of the second substrate. The proposed feed mechanism gets rid of the otherwise bulky balun. The Bowtie antenna is a compact solution with dimensions of 32 $\times $ 32 $\times\,\,33.8$ mm3. Measured results have verified that the antenna operates over a frequency range of 3.1–5 GHz and exhibits an average gain and antenna efficiency in the vertical and horizontal polarizations of 7.5 dBi and 82.6%, respectively.

39 citations


Journal ArticleDOI
TL;DR: In this article , a small printed bowtie-shaped microstrip antenna with meandered arms is proposed to support various fifth generation (5G) wireless applications, which can serve or reject a variety of applications such as wireless fidelity (Wi-Fi), sub-6 GHz, and ultra wideband (UWB) communications due to its multiband characterization and optimized rejection bands.
Abstract: To support various fifth generation (5G) wireless applications, a small, printed bowtie-shaped microstrip antenna with meandered arms is reported in this article. Because it spans the broad legal range, the developed antenna can serve or reject a variety of applications such as wireless fidelity (Wi-Fi), sub-6 GHz, and ultra-wideband (UWB) 5G communications due to its multiband characterization and optimized rejection bands. The antenna is built on an FR-4 substrate and powered via a 50-Ω microstrip feed line linked to the right bowtie’s side. The bowtie’s left side is coupled via a shorting pin to a partial ground at the antenna’s back side. A gradually increasing meandering microstrip line is connected to both sides of the bowtie to enhance the rejection and operating bands. The designed antenna has seven operating frequency bands of (2.43–3.03) GHz, (3.71–4.23) GHz, (4.76–5.38) GHz, (5.83–6.54) GHz, (6.85–7.44) GHz, (7.56–8.01) GHz, and (9.27–13.88) GHz. The simulated scattering parameter S11 reveals six rejection bands with percentage bandwidths of 33.87%, 15.73%, 11.71, 7.63%, 6.99%, and 12.22%, respectively. The maximum gain of the proposed antenna is 4.46 dB. The suggested antenna has been built, and the simulation and measurement results are very similar. The reported antenna is expanded to a four-element design to investigate its MIMO characteristics.

32 citations


Journal ArticleDOI
14 Feb 2022-Frequenz
TL;DR: In this article , a branch microstrip coupler with the simple structure using T-shaped resonators and open-ended stubs at 1.8 GHz was designed and fabricated.
Abstract: Abstract In this paper, a compact branch microstrip coupler with the simple structure using T-shaped resonators and open-ended stubs at 1.8 GHz is designed and fabricated. The proposed coupler creates two transmission zeros at 3.4 and 3.87 GHz, with more than 50 dB attenuation level, which resulted in a good harmonic suppression at 2nd harmonic. Artificial neural network (ANN) has been utilized to extract the transfer function of the proposed coupler resonator for the first time, so the values of the transmission zeros can be located in the desired frequency. This technique can also be used for the other electrical devices. The designed device has a small size of 28 mm × 30 mm (0.9 λ × 0.95 λ), which shows more than 35% size reduction compared to the typical branch-line coupler with λ/4 branch lines. The proposed coupler is simulated using Advanced Design System (ADS) software and fabricated on Rogers Duroid 5880 substrate (ε r = 2.2, h = 31 mil). The simulation and measurement results verify the correct performance of the designed coupler.

32 citations


Journal ArticleDOI
TL;DR: In this paper , the authors proposed a composite microstrip/coplanar waveguide line (CM/CPW line) to achieve circuit miniaturization by consolidating microstrip lines (MLs) and coplanar Waveguide (CPW) lines on a single dielectric substrate.
Abstract: The rapid development of modern communication systems propels the demand of high performance and miniaturization of RF/microwave components. Power dividers and filters are indispensable circuit components in amplifiers and antenna feed-networks which occupy large footprint of circuit broads, particularly at low frequency. The purpose of this study is to initiate a new type of planar transmission line with unique dual signal-path characteristics and ultimately achieve circuit miniaturization. In this paper, a novel technique of consolidating microstrip lines (MLs) and coplanar waveguide (CPW) lines on a single dielectric substrate, designated as the composite microstrip/CPW line (CM/CPW line), is proposed. With reference to the average line length of ML and CPW, it warrants a physical length reduction of 48.3% and further achieves a reduction of 80.8% after zigzagging CM/CPW line. The proof-of-concept design example of a two-way Wilkinson power divider (WPD) has demonstrated the effectiveness of the miniaturization technique. The simulation, in combination with the experimental results, validates that a size reduction factor of 86.9% when compared to conventional one has been achieved while maintaining a fractional bandwidth of 57.7% for the WPD.

26 citations


Journal ArticleDOI
TL;DR: Different switching techniques for frequency Reconfigurable Antenna (RA) and formulations for the parameters of Microstrip Patch Antenna and slot insertion and generic interconnections of switches for antenna array is addressed for RA design.
Abstract: This paper discusses a review of frequency reconfigurability through switches for 5G applications. A new switching technique (varying values of lumped parameters) for frequency reconfiguration is analysed and validated by investigation a difference between a simple (non-reconfigurable) and a reconfigurable antenna for 60 GHz resonant frequency. Different switching techniques for frequency Reconfigurable Antenna (RA) and formulations for the parameters of Microstrip Patch Antenna and slot insertion. Generic interconnections of switches for antenna array is addressed for RA design. important aspect of this paper is that these techniques have been discussed for the frequency switching of Reconfigurable microstrip antennas designed for 5G applications i.e. their frequency of operation is in millimetre-wave range (>6GHz).

23 citations


Journal ArticleDOI
TL;DR: In this paper , a metasurface-based circularly polarized (CP) microstrip patch antenna with high performance in terms of the global bandwidth and gain is presented, where the antenna configuration was a square-modified micro-strip patch that was sandwiched between a meeting surface and the ground plane.
Abstract: A metasurface-based circularly polarized (CP) microstrip patch antenna with high performance in terms of the global bandwidth and gain is presented. The antenna configuration was a square-modified microstrip patch that was sandwiched between a metasurface and the ground plane. The metasurface comprised a $4 \times 4$ array of square patches, while the single-feed radiating microstrip patch had axial ratio (AR) tuning stubs and a crossed slot. Under excitation, the microstrip patch and crossed slot, in conjunction with the metasurface, generated multiple resonances and AR minimum points that combined to produce large global bandwidths with regard to the impedance, AR, and 3 dB gain. Using a stacked layout, a low-profile design with the dimensions of $54\,\,\text {mm} \times 54\,\,\text {mm} \times 3.1$ mm ( $1.2\,\,\lambda _{\text {o}} \times 1.2\,\,\lambda _{\text {o}}\times 0.07\,\,\lambda _{\text {o}}$ at 6.8 GHz) was obtained, which generated a highly stable broadside gain above 10 dBic throughout the entire operating AR bandwidth. This antenna had a measured −10 dB impedance bandwidth of 5.62–11.04 GHz (65.06%) and a 3 dB AR bandwidth of 5.64–7.89 GHz (33.25%). In addition, it had a measured 3 dB gain bandwidth of 5.17–8.2 GHz (45.32%), with a measured peak gain of 12.17 dBic.

15 citations


Journal ArticleDOI
01 Jun 2022-Sensors
TL;DR: In this paper , a quad-band polarization-insensitive metamaterial absorber (MMA) was proposed for Ku-and K-band applications, which consists of two square split-ring resonators (SSRR), four microstrip lines, and an inner Jerusalem cross to generate four corresponding resonances at 12.62 GHz, 14.12 GHz, 17.53 GHz, and 19.91 GHz with 97, 99.51, 99, and 99.5% absorption, respectively.
Abstract: The development of metamaterial absorbers has become attractive for various fields of application, such as sensing, detectors, wireless communication, antenna design, emitters, spatial light modulators, etc. Multiband absorbers with polarization insensitivity have drawn significant attention in microwave absorption and sensing research. In this paper, we propose a quad-band polarization-insensitive metamaterial absorber (MMA) for Ku- and K-band applications. The proposed patch comprises two square split-ring resonators (SSRR), four microstrip lines, and an inner Jerusalem cross to generate four corresponding resonances at 12.62 GHz,14.12 GHz, 17.53 GHz, and 19.91 GHz with 97%, 99.51%, 99%, and 99.5% absorption, respectively. The complex values of permittivity, permeability, refractive index, and impedance of MMA were extracted and discussed. The absorption mechanism of the designed MMA was explored by impedance matching, equivalent circuit model, as well as magnetic field and electric field analysis. The overall patch has a rotational-symmetrical structure, which plays a crucial role in acquiring the polarization-insensitive property. The design also shows stable absorption for both transverse electric (TE) and transverse magnetic (TM) modes. Its near-unity absorption and excellent sensing performance make it a potential candidate for sensing applications.

Journal ArticleDOI
TL;DR: In this paper , a modified design of the rectangular Microstrip Patch Antenna (MPA) beside edge feeding technique is simulated and optimised to cover a multi-band of the microwave frequency.
Abstract: The microstrip patch antenna is commonly recognised for its diversity in term of achievable structures that make them appropriate to a wide variety of applications. The lightweight and compact size of the structure make these types of antennas suitable for use besides the microwave embedded circuits two more of their diverse benefits. In this paper, a modified design of the rectangular Microstrip Patch Antenna (MPA) beside edge feeding technique is simulated and optimised to cover a multi-band of the microwave frequency. The proposed antenna has been analysed based on the High-Frequency Structure Simulator (HFSS) using an FR-4 substrate. The introduced MPA design constitutes of a radiating patch from copper metal with a copper extension directly coupled to the lowest edge of the radiating patch via three stubs to covering three operating frequency bands: f1= 6.19 GHz (6.13-6.26 GHz), f2= 7.63 GHz (7.55-7.7 GHz), and f3=10 GHz (9.3-10.82 GHz). Consequently, the obtained results of the modified antenna design show a good gain with S11<10 dB in the previous operating frequency bands, which are suitable for most wireless communication applications.

Journal ArticleDOI
TL;DR: In this article , the authors explore the current advancements and new opportunities in SIW implementation of RF and microwave devices including filters, multiplexers (diplexers and triplexers), power dividers/combiners, antennas, and sensors for modern communication systems.
Abstract: Substrate-integrated waveguide (SIW) is a modern day (21st century) transmission line that has recently been developed. This technology has introduced new possibilities to the design of efficient circuits and components operating in the radio frequency (RF) and microwave frequency spectrum. Microstrip components are very good for low frequency applications but are ineffective at extreme frequencies, and involve rigorous fabrication concessions in the implementation of RF, microwave, and millimeter-wave components. This is due to wavelengths being short at higher frequencies. Waveguide devices, on the other hand, are ideal for higher frequency systems, but are very costly, hard to fabricate, and challenging to integrate with planar components in the neighborhood. SIW connects the gap that existed between conventional air-filled rectangular waveguide and planar transmission line technologies including the microstrip. This study explores the current advancements and new opportunities in SIW implementation of RF and microwave devices including filters, multiplexers (diplexers and triplexers), power dividers/combiners, antennas, and sensors for modern communication systems.

Journal ArticleDOI
TL;DR: In this paper , a simple technique for achieving frequency reconfigurability is proposed using a single PIN diode, where the location of the feed and slot of the patch is varied for locating the best performing points.
Abstract: The simple technique for achieving frequency reconfigurability is proposed using a single PIN diode. Biasing complexity is minimized by attaching the PIN diode at the top of the design. The presented design provides the directivity of 6.98 dB, minimum reflectance coefficient (S 11 ) of −22.56 dB, normalized directivity of 88°, and a total gain of 3.683 dB. The multiple bands of frequency tunability behaviour with the maximum frequency reconfigurability of 100 MHz. The location of the feed and slot of the patch is varied for locating the best performing points. The FR4 based lower profile dielectric helps cost reduction and mass production. The simulation is carried out using the HFSS simulator. The fabrication of the presented work is also included and compared with simulated results. The presented work is suitable for Wi-Max, 5G and WLAN applications.

Journal ArticleDOI
TL;DR: In this article , a multi-layered microstrip line with built-in parallel-plate capacitors is proposed for DC-blocking applications, with its transmission characteristics measured up to 50 GHz.
Abstract: In this paper, a novel multi-layered microstrip line with built-in parallel-plate capacitors is proposed for DC-blocking applications, with its transmission characteristics measured up to 50 GHz. The microstrip lines are fabricated via screen printing directly onto polyurethane films laminated on standard textile substrates which would otherwise be unsuitable for printing. Compared to a standard microstrip line on the same substrate, the proposed 10 cm-long line on felt (with an embedded 44 pF capacitance) suffers from less than 0.1 dB higher insertion loss up to 4 GHz. Furthermore, varying the overlapping length of the lines and hence the capacitance enables the realization of DC blocking and $-$ 3 dB high-pass filtering with pass-bands starting between 88 MHz and 1.2 GHz. This is achieved without altering the cut-off frequency of the microstrip line’s mode-free propagation, measured up to 50 GHz, exhibiting a low attenuation of 0.32 dB/mm at 50 GHz on a felt fabric substrate. Compared to a lumped capacitor, the proposed microstrip-embedded printed capacitor demonstrates a significant improvement in mechanical reliability, withstanding over 10,000 bending cycles, and RF power handling with under 6 $^{\circ }$ C temperature rise at 1 W. The lines are fabricated on two textile substrates and their transmission characteristics were measured up to 50 GHz, which represents the highest frequency characterization of textile-based lines to date, demonstrating a stable group delay and insertion losses. Based on the proposed multi-layered integration method, low-cost screen-printed microstrip-embedded capacitors on textiles can be used for microwave applications up to mmWave bands.

Journal ArticleDOI
TL;DR: In this paper , a novel, highly selective, and compact filter with controllable transmission zeros (TZs) is proposed, where the negative magnetic coupling was introduced through a full-wavelength microstrip line resonator and the additional TZ was added by the crosscoupling of indirectly connected resonators in the traditional box-like topology.
Abstract: A novel, highly selective, and compact filter with controllable transmission zeros (TZs) is proposed in this brief. The hybrid structure of the proposed filter is based on the substrate integrated waveguide (SIW) and microstrip line resonators. The negative magnetic coupling was introduced through a full-wavelength microstrip line resonator, and the additional TZ was added by the cross-coupling of indirectly connected resonators in the traditional box-like topology. Consequently, high selectivity is achieved with TZs located at both sides of the passband. The independent control of the left and right TZs can be realized by controlling the cross-coupling and external coupling. The proposed work achieves good performance, including sharp skirt characteristics, compact size, and low loss. As a validation of the concept and performance, a filter prototype designed following the procedure is fabricated and measured.

Journal ArticleDOI
TL;DR: In this paper , a 1-bit wideband electronically reconfigurable reflectarray (RRA) in Ku-band is proposed, where the stacked microstrip structure and a 1 bit “microstrip line-slot line microstrip line&#x 201D; phase shifter (MSMPS) were introduced in order to achieve the wideband and recomfigurable characteristics.
Abstract: In this paper, a 1-bit wideband electronically reconfigurable reflectarray (RRA) in Ku-band is proposed. In order to achieve the wideband and reconfigurable characteristics, the stacked microstrip structure and a 1-bit “microstrip line-slot line-microstrip line” phase shifter (MSMPS) were introduced in this design. A novel “receiving-phase shift-transmitting” unit cell was gotten by connecting two stacked microstrip structures using MSMPS. Due to the receiving and transmitting parts are perpendicular to each other, the polarization rotation characteristic was demonstrated. To avoid the blockage of the feed horn, it was placed above the reflecting surface array with an offset angle of 25° to the normal direction. A $16\times16$ obliquely-fed RRA was designed and fabricated. The measured 1-dB gain bandwidth of the RRA is 15.4%. The measured results show that the fabricated prototype can achieve beam scanning from −20° to 50° in the elevation plane, and ±50° beam scanning in the azimuth plane.

Journal ArticleDOI
TL;DR: In this paper , a metamaterial implementation was used to improve low-profile microstrip antennas as ultra-wideband (UWB) applications, which consists of variations of one to four hexagonal shape split ring resonator (SRR-H) elements.
Abstract: A metamaterial is any material engineered with a property not discovered in naturally occurring materials. Its existence is important in the development and application of modern technology in this century. Furthermore, Its characteristics such as high sensitivity and gain can be potentially applied in antenna technology. In this research, the metamaterial implementation was used to improve low-profile microstrip antennas as ultra-wideband (UWB) applications. The proposed metamaterial consists of variations of one to four hexagonal shape split ring resonator (SRR-H) elements. This study was carried out through simulation and experiments which were operated in the frequency range 0.05–9 GHz. Based on the results, the proposed antenna with the variation of the SRR-H elements provides increased performance than the without SRR-H. The highest double-negative (DNG) metamaterial characteristic of the SRR-H four-element structure provides the highest antenna performance compared to others. The given working frequency occurs at 5.98 GHz with an increase in bandwidth of 47.49% from without SRR-H. The antenna metamaterial structure also responds by providing an ultimate gain radiation pattern of 5.97 dBi at a 45-degree angle in the Quadrant II region. Thus, the performance of the proposed antenna shows the potential for use in UWB technology.

Journal ArticleDOI
TL;DR: In this paper , coupled line and T-shaped microstrip structures are used to construct four types of quasi-reflectionless (QR) filters, including single and two-port QR bandpass filters (BPFs) and bandstop filters (BSFs).
Abstract: In this paper, two simple structures, i.e., coupled line and T-shaped microstrip structures, are used to construct four types of quasi-reflectionless (QR) filters, including single-and two-port QR bandpass filters (BPFs) and bandstop filters (BSFs). First, the characteristics of the coupled line and T-shaped microstrip structures are analyzed in details using each two electrical parameters. Then, the single-port QR BPF and BSF are designed using duplexer architectures formed by these two simple structures. Subsequently, the two-port QR BPF and BSF are constructed through loading an additional absorption channel near the output port based on the architectures of single-port QR filters. The relations between the fractional bandwidth (FBW) of each type of QR filters and 3-dB FBWs of the two simple structures are provided, which give a guidance of the QR filter design with desired specifications. Moreover, a brief design procedure for the proposed QR filters is summarized. Finally, to validate the feasibility of the proposed approach, two proof-of-concept microstrip prototypes of the two-port QR filters are fabricated, whose simulations and measurements agree well with each other. This work will facilitate the design of QR filters with different desired specifications and simplify their design procedures.

Journal ArticleDOI
TL;DR: In this article , a microstrip line loaded with a dumbbell-shaped defect ground structure (DB-DGS) is used for complex permittivity measurements, defined as the variation in the resonance frequency and depth caused by the material under test (MUT), when it is put in contact with the sensitive region of the device.
Abstract: It is shown in this paper that a microstrip line loaded with a dumbbell-shaped defect ground structure (DB-DGS) is useful for complex permittivity measurements. The working principle of the sensor is the variation in the notch (resonance) frequency and depth caused by the material under test (MUT), when it is put in contact with the sensitive region of the device, i.e., the capacitive slot. It is demonstrated that the relative sensitivity of the sensor, defined as the variation of the resonance frequency of the DB-DGS with the dielectric constant of the MUT relative to the resonance frequency of the bare structure, does not depend on the geometry of the DB-DGS, provided the substrate is thick enough. The relative sensitivity, the key figure of merit, is dictated by the equivalent dielectric constant of the substrate, and it increases as the substrate permittivity decreases. Using the circuit model of the sensing structure, simple analytical expressions providing the dielectric constant and the loss tangent of the MUT are derived. Such analytical formulas depend on the notch frequency and depth of the sensor with and without MUT in contact with it, i.e., easily measurable quantities. The analysis carried out is corroborated through full-wave electromagnetic simulation and experiments.

Journal ArticleDOI
TL;DR: In this paper , an ultra-wideband (UWB) bandpass-filtering microstrip circuit with an embedded in-band transmission zero (TZ) for co-integrated angular displacement RF sensing is reported.
Abstract: An ultra-wideband (UWB) bandpass-filtering microstrip circuit with an embedded in-band transmission zero (TZ) for co-integrated angular displacement RF sensing is reported. It is based on a two-layer structure that exploits a combination of a UWB transversal filtering section (TFS) with a parallel-coupled-line (PCL) path and a U-shaped slotline acting as the stator and a semi-circular slotline acting as the rotor. As the rotor consisting of a semi-circular slotline rotates, the degree of coupling between the slotline of the stator and the rotor is altered in a contactless fashion, thus varying the stator slotline effective lengths and, hence, the in-band TZ location and its rejection depth that enable to perform the rotation-RF-sensing task. The equivalent circuit model of the engineered dual-functionality UWB bandpass filtering/ angular displacement sensing RF device is provided, together with a numerical/parametric evaluation to study its performance. The sensing capability is analyzed for an example circuit built with a UWB bandpass filtering transfer function centered at 1.8 GHz with a fractional bandwidth of 110%. Furthermore, a proof-of-concept microstrip prototype with an angular rotation range of 90° is developed and tested to validate this approach experimentally. The average frequency sensitivity in terms of the variation of the in-band TZ location is 2.27 MHz/°, showing enhanced linearity and contactless operation as added merits compared with prior-art TFS-based rotational angle sensors.

Journal ArticleDOI
TL;DR: In this paper , a sensor based on a pair of parallel lines coupled resonators and a cleft arranged in the coupling region is proposed to hold the samples under test (SUTs).
Abstract: In this work, a sensor in microstrip technology and a methodology for measuring the real part and the imaginary part of the complex uniaxial permittivity of solid anisotropic samples are presented. The sensor is based on a pair of parallel lines coupled resonators and a cleft arranged in the coupling region which allows to hold the samples under test (SUTs). The proposed methodology relates the change in the even/odd resonance frequency with the real part of the permittivity in the vertical/horizontal direction, and the change in the Q factor of the even/odd mode with the imaginary part of the permittivity in the vertical/horizontal direction. The methodology was successfully verified with the characterization, at 2.43 GHz of anisotropic samples of printed PLA, Diclad 880, and RO4350B using the knowns materials: RT5870, PTFE and RO4003.

Journal ArticleDOI
TL;DR: In this paper , a two-port microstrip-fed rectangular patch resonating structure printed on a 20 × 28 mm2 Roger RO3035 substrate with a thickness of 0.75 mm, a relative permittivity of 3.5, and a loss tangent of 1.0015.
Abstract: In this paper, we present the design of a compact and highly sensitive microwave sensor based on a metamaterial complementary split-ring resonator (CSRR), for liquid characterization at microwave frequencies. The design consists of a two-port microstrip-fed rectangular patch resonating structure printed on a 20 × 28 mm2 Roger RO3035 substrate with a thickness of 0.75 mm, a relative permittivity of 3.5, and a loss tangent of 0.0015. A CSRR is etched on the ground plane for the purpose of sensor miniaturization. The investigated liquid sample is put in a capillary glass tube lying parallel to the surface of the sensor. The parallel placement of the liquid test tube makes the design twice as efficient as a normal one in terms of sensitivity and Q factor. By bending the proposed structure, further enhancements of the sensor design can be obtained. These changes result in a shift in the resonant frequency and Q factor of the sensor. Hence, we could improve the sensitivity 10-fold compared to the flat structure. Subsequently, two configurations of sensors were designed and tested using CST simulation software, validated using HFSS simulation software, and compared to structures available in the literature, obtaining good agreement. A prototype of the flat configuration was fabricated and experimentally tested. Simulation results were found to be in good agreement with the experiments. The proposed devices exhibit the advantage of exploring multiple rapid and easy measurements using different test tubes, making the measurement faster, easier, and more cost-effective; therefore, the proposed high-sensitivity sensors are ideal candidates for various sensing applications.

Proceedings ArticleDOI
21 Jan 2022
TL;DR: In this paper , a Microstrip Patch Antenna is designed and studied for the future wireless communication technology operated at 2.4 GHz and the suggested antenna design is modeled with the help of the CST studio suite.
Abstract: In this research, A Microstrip Patch Antenna is designed and studied for the future Wireless communication technology operated at 2.4 GHz. Rogers RT/Duroid5880 is used as substrate having a dielectric loss of 2.2 and a thickness of 0.3451 mm. The suggested antenna design is modeled with the help of the CST studio suite. The motive of this research was to achieve lower Return Loss, higher gain and lower VSWR. From the simulation, the Return Loss, Gain and VSWR were found to be −13.89 dB, 6.66 dBi and 1.50 respectively.

Journal ArticleDOI
TL;DR: In this article , a sub-6 GHz microstrip patch antenna operating at three resonant frequencies 3.6, 3.9, and 4.9 GHz is designed for 5G applications.
Abstract: |A novel recon(cid:12)gurable sub-6 GHz microstrip patch antenna operating at three resonant frequencies 3.6, 3.9, and 4.9 GHz is designed for 5G applications. The proposed antenna is constructed from metamaterial (MTM) array with a matching circuit printed around a printed strip line. The antenna is excited with a coplanar waveguide to achieve an excellent matching over a wide frequency band. The proposed antenna shows excellent performance in terms of S 11 , gain, and radiation pattern that are controlled well with two photo resistance. The proposed antenna shows different operating frequencies and radiation patterns after changing the of photo resistance status. The main antenna novelty is achieved by splitting the main lobe that tracks more than one user at the same resonant frequency. Nevertheless, the main radiation lobe can be steered to the desired location by controlling the surface current motion using two varactor diodes on a matching circuit.

Journal ArticleDOI
TL;DR: In this article , a surrogate-assisted defected ground structure (DGS) design is proposed to suppress plane couplings simultaneously in a 2 × 2 microstrip antenna array at 2.45 GHz.
Abstract: A surrogate-assisted defected ground structure (DGS) design is proposed to suppress E- and H- plane couplings simultaneously in a 2 × 2 microstrip antenna array at 2.45 GHz. The DGS is designed and analyzed based on the magnetic current and mode theory. Machine learning is employed to sweep the DGS parameters within defined limits and fine-tune them to obtain optimal design, predominantly shortening the DGS design time. A 2 × 2 microstrip antennas array is used as a test case to corroborate the efficacy of the proposed scheme. Simulation and measurement results show that the proposed DGS can significantly reduce E- and H- plane couplings.

Journal ArticleDOI
TL;DR: In this article , a ladder resonator is introduced to reduce mutual coupling effect in the patch antenna array structure, which blocks the surface current between two patch antennas at the operating frequency, which results in mutual effect reduction.
Abstract: In this paper a novel ladder resonator is introduced to reduce mutual coupling effect in the patch antenna array structure. Applied patch antennas are operating at 2.45 GHz frequency, which specially used for MIMO (multiple input multiple output) systems. The edge-to-edge distance between two microstrip patch antennas is 0.05 λ. The proposed ladder resonator impressively blocks the surface current between two patch antennas at the operating frequency, which results in mutual effect reduction. The designed configuration has been analyzed, simulated and measured. Scattering parameters with and without of proposed resonator has been investigated. The result shows that, the proposed configuration increases isolation between two microstrip patch antennas about 44 dB.

Journal ArticleDOI
Moein Navaei1
TL;DR: In this paper , the human milk dielectric constant by a microwave sensor has been evaluated and the proposed sensor is result of coupling between a simple microstrip line and a split ring resonator and its resonance frequency is 6 GHz.
Abstract: In this paper, the human milk dielectric constant by a microwave sensor has been evaluated. The proposed sensor is result of coupling between a simple microstrip line and a split ring resonator and its resonance frequency is 6 GHz. When up to 30 μl of milk are placed on the sensing area on the sensor, it causes the resonance frequency to shift. Six samples of human milk were measured by a network analyzer, then the dielectric constant of the samples were determined, and three similar samples were measured by the built-in sensor. The proposed microwave sensor has Q-factor of 38 and its sensitivity is 0.17%. The implemented sensor has acceptable performance compared to previous sensors and it can be used to determine the normal behavior of human milk with a simple method and for this work, it requires to small value of sample for measurement.

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TL;DR: In this article , a waveguide-to-microstrip inline transition was proposed using a wedge-waveguide iris to form an ultra-compact U-bend waveguide.
Abstract: A novel waveguide-to-microstrip inline transition was proposed using a wedge-waveguide iris to form an ultra-compact U-bend waveguide. The wedge-waveguide iris not only functioned as a wide wall of the height-reduced waveguide for the $E$ -plane probe, but also played a critical role in impedance matching and parasitic resonance suppression. The working principle was investigated through theoretical analysis and full-wave simulation, and the relevant design processes for the transition were discussed. Moreover, two back-to-back transition prototypes, one working at the $W$ -band and the other working at the WR4.3 band, were designed, fabricated, and measured. The back-to-back prototypes obtained an insertion loss of less than 0.8 and 1.2 dB, with a return loss better than 15 dB in the $W$ -band and WR4.3 band, respectively. The measurement results were consistent with simulation results. A miniaturized 110-GHz tripler incorporating this transition for inline output was fabricated. A conversion efficiency of 2.5%–3.6% was achieved in 90–120 GHz at 100-mW driving power.

Journal ArticleDOI
TL;DR: In this paper , two types of coplanar stripline (CPS)-based multimode stepped-impedance resonators are proposed for exploration of wideband balanced filters with intrinsic common-mode (CM) suppression.
Abstract: In this paper, two types of coplanar stripline (CPS)-based multimode stepped-impedance resonators are proposed for exploration of wideband balanced filters with intrinsic common-mode (CM) suppression. Such CPS multimode resonators (MMRs) can be readily terminated with either a pair of open- or short-circuited ends with no need of via holes. With resorting to a proper impedance ratio, the first three modes of each MMR are assembled to construct a wide differential-mode (DM) passband. Afterwards, two distinctive broadside-coupled sections are further investigated based on their open- and short-ended circuit models, respectively. Characteristic impedances and effective dielectric constants can be adequately obtained by virtue of an efficient quasi-static approach under the odd- and the even-mode operations. As such, two types of CPS-MMR-based bandpass filters each with five transmission poles are synthetically designed. For experimental validation, the proposed balanced filters are finally fabricated and measured with the help of two identical pairs of balanced-to-balanced microstrip-to-CPS transitions. Theoretical, simulated, and measured results are found in reasonable agreement with each other with/without the transitions, thus demonstrating that the proposed CPS-based MMRs are well characterized with the wideband DM transmission and intrinsic CM suppression.