Showing papers on "Coplanar waveguide published in 2021"
TL;DR: A novel sensor for detecting and measuring angular rotation and proximity, intended for rapid prototyping machines, based on a complementary split-ring resonator driven by a conductor-backed coplanar waveguide, which has a planar topology.
Abstract: This article presents a novel sensor for detecting and measuring angular rotation and proximity, intended for rapid prototyping machines. The sensor is based on a complementary split-ring resonator (CSRR) driven by a conductor-backed coplanar waveguide (CBCPW). The sensor has a planar topology, which makes it simple and cost-effective to produce and accurate in measuring both physical quantities. The sensor has two components, a rotor and a stator: the first of these (the CSRR) can rotate around its axis and translate along the plane normal to the ground of the CBCPW. A detailed theoretical and numerical analysis, along with a circuit model, of the unique sensor design is presented. The proposed sensor exhibits linear response for measuring angular rotation and proximity in the range of 30°–60° and 0–200 μm, respectively. Another distinctive feature of the rotation and proximity sensor is the wide frequency band of applicability, which is an integral part of its novel design and is implemented through various dielectric material loadings on the CSRR. In the prototype of the proposed device, the stator (CBCPW) is fabricated on a 0.508-mm-thick RF-35 substrate, whereas the CSRR-based rotor is fabricated on TLY-5 and RF-35 substrates. The angular rotation, proximity, operating band selection, and sensitivity are measured using a vector network analyzer and are found to be good matches to the simulated and theoretical results.
41 citations
TL;DR: In this article, a full ground ultra wideband (UWB) antenna is proposed and utilized to attain a broad bandwidth while keeping specific absorption rate (SAR) in the acceptable range based on both 1 g and 10 g standards.
Abstract: Wireless body area network (WBAN) applications have broad utility in monitoring patient health and transmitting the data wirelessly. WBAN can greatly benefit from wearable antennas. Wearable antennas provide comfort and continuity of the monitoring of the patient. Therefore, they must be comfortable, flexible, and operate without excessive degradation near the body. Most wearable antennas use a truncated ground, which increases specific absorption rate (SAR) undesirably. A full ground ultra-wideband (UWB) antenna is proposed and utilized here to attain a broad bandwidth while keeping SAR in the acceptable range based on both 1 g and 10 g standards. It is designed on a denim substrate with a dielectric constant of 1.4 and thickness of 0.7 mm alongside the ShieldIt conductive textile. The antenna is fed using a ground coplanar waveguide (GCPW) through a substrate-integrated waveguide (SIW) transition. This transition creates a perfect match while reducing SAR. In addition, the proposed antenna has a bandwidth (BW) of 7-28 GHz, maximum directive gain of 10.5 dBi and maximum radiation efficiency of 96%, with small dimensions of 60 × 50 × 0.7 mm3. The good antenna's performance while it is placed on the breast shows that it is a good candidate for both breast cancer imaging and WBAN.
41 citations
TL;DR: The transmission line is the most basic component of microwave and mm-wave circuits and systems, and its characteristics-including loss, size, integration, cost, and weight-directly or indirectly affect the performance of the entire circuit as discussed by the authors.
Abstract: With the rapid development of modern communication and radar technology, there is a need for the miniaturization, planarization, and modularization of microwave and millimeter-wave (mm-wave) systems, without losing excellent performance and reliability. The transmission line is the most basic component of microwave and mm-wave circuits and systems, and its characteristics-including loss, size, integration, cost, and weight-directly or indirectly affect the performance of the entire circuit and system. Commonly used transmission lines [1] include nonplanar transmission lines, such as a metal waveguide and coaxial line, and planar transmission lines, such as a microstrip, strip line, coplanar waveguide, and slot line.
40 citations
TL;DR: The results show that the proposed CA is polarization and 3-D orientation insensitive and provides good MIMO properties, which makes it a suitable choice to transfer high data rate to an external antenna of diverse polarization.
Abstract: This article presents a first of its kind, coplanar waveguide (CPW)-fed 3-D multi-input-multi-output (MIMO) ground radiating cubic antenna (CA), implantable in the human upper arm for biotelemetry applications. The four antenna elements are circular in shape and loaded with a pair of slots to obtain circular polarization (CP). It excites diversified CP radiation in Industrial, Scientific, and Medical (ISM) band 2.45 and 5.8 GHz in orthogonal space to establish communication between the human body moving in random directions and base-station. The overall dimensions of the proposed antenna are $15\,\, {\times }\,\,15\,\, {\times }\,\,15$ mm3. Monitoring circuit PCB is placed at the top, and the bottom side of the cube and central hollow space is filled with a dry solid phantom for impedance matching. The CA is simulated in the vicinity of the canonical arm tissue model in HFSS software and examined in a realistic human model. The far-field gain is −18.5 dB with −32 dB isolation between elements. The CA is fabricated, and measurements are carried out in skin-fat-muscle phantom and minced pork. Simulated results closely match with measured results. The results show that the proposed CA is polarization and 3-D orientation insensitive and provides good MIMO properties. The low SAR value of the CA allows maximum transmit power of 5.81 mW, makes it a suitable choice to transfer high data rate (200 Mb/s) to an external antenna of diverse polarization. These features make CA an attractive solution for real-time healthcare applications.
39 citations
TL;DR: In this article, a one-port reflective-mode phase-variation microwave sensor consisting of a coplanar waveguide (CPW) transmission line terminated with a grounded open complementary split ring resonator (OCSRR) is presented for measuring the dielectric constant of the material under test (MUT), which should be placed in contact with the OCSRR, the sensitive element.
Abstract: This paper presents a one-port reflective-mode phase-variation microwave sensor consisting of a coplanar waveguide (CPW) transmission line terminated with a grounded open complementary split ring resonator (OCSRR). The sensor is useful for measuring the dielectric constant of the so-called material under test (MUT), which should be placed in contact with the OCSRR, the sensitive element. The output variable is the phase of the reflection coefficient. Design guidelines for the implementation of highly sensitive sensors are derived in the paper, and validated through simulation and experiment. As compared to other reflective-mode phase-variation sensors based on open-ended sensing lines, the designed and fabricated devices exhibit a very small sensitive region by virtue of the use of an electrically small resonant element, the OCSRR. The relevant figure of merit, defined as the ratio between the maximum sensitivity and the size of the sensing area (expressed in terms of the squared wavelength), is as high as FoM $= 5643^{\circ }/\lambda ^{2}$ in one of the reported prototypes. Moreover, the paper analyzes the effects of losses. From this study, it is concluded that MUT losses do not significantly affect the output variable, provided losses are small. It is also demonstrated that the sensor is useful to estimate the loss tangent of the considered MUT samples.
37 citations
TL;DR: In this article, a coplanar waveguide (CPW) feed structure with a modified inverted L-shaped radiating patch is presented, and a single-layer non-uniform frequency selective surface (FSS) composed of rectangular conductive patches is designed and used with the CP antenna to improve the CP characteristics and the gain of the antenna.
Abstract: This paper presents a new ultra-wideband (UWB) antenna system with circular polarization (CP). The antenna is a coplanar waveguide (CPW) feed structure with a modified inverted L-shaped radiating patch. A single-layer non-uniform frequency selective surface (FSS) composed of rectangular conductive patches is designed and used with the CP antenna to improve the CP characteristics and the gain of the antenna. According to the measured results, the 10 dB return-loss bandwidth of the antenna with the FSS extends from 3.7 to 11.1 GHz. The 3-dB measured axial ratio (AR) bandwidth is 58.15%, covering 5 to 9.1 GHz, and the measured peak gain is 4–9.4 dBi, showing an increase of about 3 dBi compared to theantenna without the FSS.
36 citations
TL;DR: In this article, the authors proposed a reflective-mode step-impedance transmission line based sensor for dielectric characterization of solids or liquids, which is implemented in coplanar waveguide (CPW) technology.
Abstract: Reflective-mode step-impedance transmission line based sensors for dielectric characterization of solids or liquids have been recently proposed. In this article, in order to further increase the sensitivity, the sensor is implemented in coplanar waveguide (CPW technology), and this constitutes the main novelty of this work. The sensor thus consists of a high-impedance 90° (or low-impedance 180°) open-ended sensing line cascaded to a low-impedance 90° (or high-impedance 90°) line. The output variable is the phase of the reflection coefficient, which depends on the dielectric constant of the material under test (MUT), the input variable. Placing a MUT on top of the sensing line causes a variation in the effective dielectric constant of the line, thereby modifying the phase of such line. This in turn produces a multiplicative effect on the phase of the reflection coefficient, by virtue of the step-impedance discontinuity. The main advantage of the CPW-based sensor, over other similar sensors based on microstrip technology, is the stronger dependence of the phase velocity of the sensing line with the dielectric constant of the MUT, resulting in sensitivities as high as −45.48° in one of the designed sensors. The sensor is useful for dielectric characterization of solids and liquids, and for the measurement of variables related to changes in the dielectric constant of the MUT (defect detection, material composition, etc.).
31 citations
TL;DR: In this paper, an S-shaped metasurface (MTS)-based wideband circularly polarized (CP) patch antenna was proposed for C-band uplink frequency spectrum.
Abstract: This research proposed an S-shaped metasurface (MTS)-based wideband circularly polarized (CP) patch antenna for C-band uplink frequency spectrum. The proposed MTS-based CP patch antenna was of low profile and fabricated on three substrate layers: upper, middle, and lower. The upper substrate contained $4\times 4$ periodic S-shaped MTS elements, the middle substrate functioned as ground plane with a rectangular-shaped slot at the center, and the lower substrate contained a coplanar waveguide with microstrip and ground. The S-shaped MTS elements converted linearly polarized (LP) into CP wave. Simulations were performed, and an antenna prototype was fabricated and experiments carried out. The measured impedance bandwidth and axial ratio bandwidth (ARBW) at the center frequency of 5.9 GHz were 43.22% (4.05 – 6.6 GHz) and 22% (5.3 – 6.6 GHz), respectively, rendering the proposed antenna suitable for satellite communication applications. The proposed antenna achieved the maximum gain of 6.16 dBic at 5.6 GHz. The novelty of this research lies in the use of S-shaped MTS elements to efficiently convert LP into CP wave and achieve wider ARBW for the C-band uplink spectrum.
30 citations
TL;DR: In this paper, the authors present the first broadband characterization results for the electrical properties of Ajinomoto build-up film (ABF) laminated on glass substrates.
Abstract: Glass-based packaging presents unique opportunities for supporting 5G and beyond frequencies. In this work, we present the first broadband characterization results for the electrical properties of Ajinomoto build-up film (ABF) laminated on glass substrates. ABF/glass/ABF-based stack up has been characterized from 20 to 170 GHz. We also report the low-loss performance of ABF/glass/ABF transmission lines. The material stack up consists of a 100- $\mu \text{m}$ -thick EN-A1 glass core from Asahi Glass Company (AGC) with 15- $\mu \text{m}$ ABF GL102 laminated on both sides. Semiadditive process (SAP) has been used to metalize the stack up. A microstrip ring resonator (MRR) method has been used to extract the dielectric constant and loss tangent of the stack up. The dispersive model estimates the dielectric constant of the stack up to be ~4.72 for the entire frequency range with a variance of +0.1. The measured loss tangent values were 0.004, 0.009, and 0.012 at 23, 103, and 140 GHz, respectively. The electrical characterization results with a confidence interval of 95% have been reported. The average insertion loss for coplanar waveguide (CPW) lines in the frequency range was measured to be between 0.055 and 0.50 dB/mm. The average insertion loss for microstrip in the same frequency range was measured to be 0.12–0.62 dB/mm. Along with the good model to hardware correlation, the performance of the transmission lines has been compared with the insertion loss published for other substrate technologies.
29 citations
TL;DR: In this article, Niobium nitride (NbN) λ / 2 coplanar waveguide resonators were fabricated from a 10-nm-thick film on silicon dioxide grown by sputter deposition.
Abstract: We characterize niobium nitride (NbN) λ / 2 coplanar waveguide resonators, which were fabricated from a 10-nm-thick film on silicon dioxide grown by sputter deposition For films grown at 180 °C, we report a superconducting critical temperature of 74 K associated with a normal square resistance of 1 k Ω, leading to a kinetic inductance of 192 pH/◻ We fabricated resonators with a characteristic impedance up to 41 k Ω and internal quality factors Q i > 10 4 in the single photon regime at zero magnetic field Moreover, in the many photon regime, the resonators present a high magnetic field resilience with Q i > 10 4 in a 6 T in-plane magnetic field and in a 300 mT out-of-plane magnetic field These findings make such resonators a compelling choice for circuit quantum electrodynamics experiments involving quantum systems with small electric dipole moments operated in finite magnetic fields
28 citations
TL;DR: In this paper, the impulse response of the fully packaged QCDs has a fullwidth at half-maximum of only 13.4×ps corresponding to a 3dB bandwidth of more than 20 GHz.
Abstract: Quantum cascade detectors (QCD) are photovoltaic mid-infrared detectors based on intersubband transitions. Owing to the sub-picosecond carrier transport between subbands and the absence of a bias voltage, QCDs are ideally suited for high-speed and room temperature operation. Here, we demonstrate the design, fabrication, and characterization of 4.3 µm wavelength QCDs optimized for large electrical bandwidth. The detector signal is extracted via a tapered coplanar waveguide (CPW), which was impedance-matched to 50 Ω. Using femtosecond pulses generated by a mid-infrared optical parametric oscillator (OPO), we show that the impulse response of the fully packaged QCDs has a full-width at half-maximum of only 13.4 ps corresponding to a 3-dB bandwidth of more than 20 GHz. Considerable detection capability beyond the 3-dB bandwidth is reported up to at least 50 GHz, which allows us to measure more than 600 harmonics of the OPO repetition frequency reaching 38 dB signal-to-noise ratio without the need of electronic amplification.
TL;DR: In this paper, the indium phosphide (InP)-based leaky-wave antennas (LWAs) are used for beam steering in mobile THz applications. But, the InP-based LWAs are based on polymer or graphene substrates and thus, it is quite impossible to monolithically integrate these antennas with state-of-the-art InPbased photonic or electronic THz sources and receivers.
Abstract: For mobile THz applications, integrated beam steering THz transmitters are essential. Beam steering approaches using leaky-wave antennas (LWAs) are attractive in that regard since they do not require complex feeding control circuits and beam steering is simply accomplished by sweeping the operating frequency. To date, only a few THz LWAs have been reported. These LWAs are based on polymer or graphene substrates and thus, it is quite impossible to monolithically integrate these antennas with state-of-the-art indium phosphide (InP)-based photonic or electronic THz sources and receivers. Therefore, in this article, we report on an InP-based THz LWA for the first time. The developed and fabricated THz LWA consists of a periodic leaking microstrip line integrated with a grounded coplanar waveguide to microstrip line (GCPW-MSL) transition for future integration with InP-based photodiodes. For fabrication, a substrate-transfer process using silicon as carrier substrate for a 50-μm thin InP THz antenna chip has been established. By changing the operating frequency from 230 to 330 GHz, the fabricated antenna allows to sweep the beam direction quasi-linearly from −46° to 42°, i.e., the total scanning angle is 88°. The measured average realized gain and 3-dB beam width of a 1.5-mm wide InP LWA are ∼11 dBi and 10°. This article furthermore discusses the use of the fabricated LWA for THz interconnects.
TL;DR: In this paper, a high-performance 0.45-0.50 GHz antenna on chip (AoC) for fabrication on a 100-micron GaAs substrate is presented.
Abstract: This paper presents the design of a high-performance 0.45–0.50 THz antenna on chip (AoC) for fabrication on a 100-micron GaAs substrate. The antenna is based on metasurface and substrate-integrated waveguide (SIW) technologies. It is constituted from seven stacked layers consisting of copper patch–silicon oxide–feedline–silicon oxide–aluminium–GaAs–copper ground. The top layer consists of a 2 × 4 array of rectangular metallic patches with a row of subwavelength circular slots to transform the array into a metasurface. This essentially enlarges the effective aperture area of the antenna. The antenna is excited using a coplanar waveguide feedline that is sandwiched between the two silicon oxide layers below the patch layer. The proposed antenna structure reduces substrate loss and surface waves. The AoC has dimensions of 0.8 × 0.8 × 0.13 mm3. The results show that the proposed structure greatly enhances the antenna’s gain and radiation efficiency, and this is achieved without compromising its physical size. The antenna exhibits an average gain and efficiency of 6.5 dBi and 65%, respectively, which makes it a promising candidate for emerging terahertz applications.
TL;DR: In this paper, a high gain and wideband circular polarization (CP) patch antenna using reflective focusing metasurface was proposed and demonstrated and the initial design of patch antenna is made of a slot planar patch radiation part fed by coplanar waveguide (CPW).
Abstract: In this paper, a high-gain and wideband circular polarization (CP) patch antenna using reflective focusing metasurface was proposed and demonstrated. The initial design of patch antenna is made of a slot planar patch radiation part fed by coplanar waveguide (CPW). The simulated return loss below −10 dB of the initial design is from 6.2 to 13.8 GHz with the relative bandwidth of 76%, and the average gain is only about 4.5 dBi. In addition, the simulated 3-dB axial ratio bandwidth (ARBW) of the initial design is 78.7% from 6 to 13.8 GHz. The antenna structure was modified to enhance the gain and radiation performance by adding the reflective focusing geometric metasurface. The metasurface with wideband high efficiency cross-polarization reflection, is arranged to construct the phase gradient paraboloid for energy gathering. Simulation results indicated that the antenna combined with reflective focusing metasurface achieves an effective wideband impedance bandwidth (return loss
TL;DR: In this paper, two configurations of a modified feather-shaped antenna element for super wideband (SWB) multiple-input multiple-output (MIMO) applications were proposed.
Abstract: Two configurations of a modified feather-shaped antenna element are proposed for super wideband (SWB) multiple-input multiple-output (MIMO) applications. The antenna element geometry comprises of a circular slot-loaded feather-shaped radiator and rectangular notch-loaded quarter elliptical coplanar waveguide ground plane. An operating bandwidth of 4.4–51.5 GHz with inter-port isolation, S21 ≥ 15 dB for spatial diversity configuration, and 3.8–51.5 GHz with S21 ≥ 15 dB in pattern diversity configuration are achieved. The footprints of the antenna configurations are 17 × 33 and 31 × 31 mm2. Both configurations exhibited an envelope correlation coefficient of <−20 dB. The proposed MIMO configurations are fabricated and experimentally validated. The designed antenna configurations are SWB and compact.
16 Feb 2021
TL;DR: In this paper, a textile-integrated energy harvesting and storage module for RF power transfer is presented, which achieves an end-to-end efficiency of 38% at 1.8 m from the transmitter.
Abstract: This paper presents a high-efficiency compact ( $0.016\lambda _{0}^{2}$ ) textile-integrated energy harvesting and storage module for RF power transfer. A flexible 50 $\mu \text{m}$ -thick coplanar waveguide rectenna filament is integrated with a spray-coated supercapacitor to realize an “e-textile” energy supply module. The meandered antenna maintains an $S_{11} dB inside and outside the fabric and in human proximity with a 2.3 dBi gain. The rectifier achieves a peak RF-DC efficiency of 80%, across a 4.5 $\text{k}\Omega $ load, and a 1.8 V open-circuit voltage from −7 dBm. The supercapacitor is directly spray-coated on a cotton substrate using carbon and an aqueous electrolyte. When connected to the supercapacitor, the rectifier achieves over an octave half-power bandwidth. The textile-integrated rectenna is demonstrated charging the supercapacitor to 1.5 V (8.4 mJ) in 4 minutes, at 4.2 m from a license-free source, demonstrating a significant improvement over previous rectennas while eliminating power management circuitry. The integrated module has an end-to-end efficiency of 38% at 1.8 m from the transmitter. On-body, the rectenna’s efficiency is 4.8%, inclusive of in-body losses and transient shadowing, harvesting 4 mJ in 32 seconds from 16.6 $\mu \text{W}$ /cm2. It is concluded that e-textile rectennas are the most efficient method for powering wearables from $\mu \text{W}$ /cm2 power densities.
TL;DR: In this article, a single-layered slot antenna system working at 5.8 GHz was proposed for in-band full duplex (IBFD) operation applications without the use of a coupler.
Abstract: A single-layered slot antenna system working at 5.8 GHz Industrial, Scientific and Medical (ISM) band is proposed for in-band full duplex (IBFD) operation applications without the use of a coupler. First, high isolation is achieved by strong separation of even- and odd-mode feeds. The microstrip-coupled coplanar waveguide (CPW) is used at Port 1 (TX port) to excite a stepped-slot antenna in the CPW odd mode. On the opposite side, a microstrip T-junction power divider is employed at Port 2 (RX port) to feed two offset-fed stepped-slot antennas in even mode. Second, isolation is further improved by 30 dB by using a lumped capacitor at the termination of the CPW. The measured isolation between the two ports is about 50 dB across the bandwidth. The measured −10 dB bandwidth of Port 1 is 0.49 GHz (8.5%), while that of Port 2 is 1.06 GHz (18.3%). The gains of TX and RX antennas are 5.4 and 5.8 dBi at 5.8 GHz. The proposed antenna can also be deployed as a dual-polarized antenna. Mathematical analysis and equivalent transmission line circuit models are provided to give physical insight into the working principals of the antenna with validation from ANSYS HFSS simulation.
TL;DR: A coplanar waveguide-fed dual-band MIMO antenna for 2.45/5.5 GHz wireless local area network (WLAN) applications is presented in this paper.
Abstract: A coplanar waveguide- (CPW-) fed dual-band multiple-input multiple-output (MIMO) antenna for 2.45/5.5 GHz wireless local area network (WLAN) applications is presented in this paper. The presented MIMO antenna consists of two identical trapezoidal radiating elements which are perpendicular to each other. The size of the entire MIMO antenna is 50 × 50 × 1.59 mm3, which is printed on a FR4 substrate. The measured impedance bandwidth of the proposed antenna is 2.25–3.15 GHz and 4.89–5.95 GHz, which can cover IEEE 802.11 a/b/g frequency bands. A rectangular microstrip stub is introduced to achieve a good isolation which is less than −15 dB in both operation frequency bands. The measured peak gain is 5.59 dBi at 2.45 GHz and 5.63 dBi at 5.5 GHz. The measured antenna efficiency is 77.8% and 80.4% in the lower and higher frequency bands, respectively. The ECC values at the lower and higher frequencies are lower than 0.003 and 0.01, respectively.
TL;DR: In this paper, a very compact dual band-notched two-port multiple-input multiple-output (MIMO) antenna with low mutual coupling is presented for portable ultra-wideband systems.
Abstract: In this paper a very compact dual band-notched two-port multiple-input multiple-output antenna with low mutual coupling is presented for portable ultra-wideband systems. This antenna with overall size 18 × 35 × 1.6 mm3, consist of two identical monopole elements which fed by two 50 Ω coplanar waveguide lines and fabricated adjacent to each other on the top side of a FR-4 substrate with shared ground plane. To reduce the mutual coupling between elements, a rectangular stub was introduced between them and then it modified to a T-shaped stub. For further reduction, a rectangular slot etched out of the connected ground plane. Due to the results, proposed antenna achieves wide impedance bandwidth at each port, from 2.3 to 12 GHz covering the whole UWB spectrum except at two eliminating bands. Although this antenna has small size and simple structure, the mutual coupling between elements is lower than −20 dB. By etching out two rectangular single complementary split-ring resonators from the radiating patch, dual band-notched characteristics are obtained in WiMAX and WLAN bands. Envelope correlation coefficient of less than 0.035, nearly omnidirectional pattern, 90% radiation efficiency despite lossy substrate, high multiplexing efficiency (>−1 dB) except at two notches and peak gain near 6dBi are some other characteristics of this design.
TL;DR: The injection of quasiparticle spin currents into a superconductor via spin pumping from an adjacent ferromagnetic metal layer is investigated and a suppression of the dampinglike torque generated in the Pt layer by the inverse spin Hall effect is observed.
Abstract: We investigate the injection of quasiparticle spin currents into a superconductor via spin pumping from an adjacent ferromagnetic metal layer. To this end, we use NbN-Ni_{80}Fe_{20}(Py) heterostructures with a Pt spin sink layer and excite ferromagnetic resonance in the Permalloy layer by placing the samples onto a coplanar waveguide. A phase sensitive detection of the microwave transmission signal is used to quantitatively extract the inductive coupling strength between the sample and the coplanar waveguide, interpreted in terms of inverse current-induced torques, in our heterostructures as a function of temperature. Below the superconducting transition temperature T_{c}, we observe a suppression of the dampinglike torque generated in the Pt layer by the inverse spin Hall effect, which can be understood by the changes in spin current transport in the superconducting NbN layer. Moreover, below T_{c} we find a large fieldlike current-induced torque.
TL;DR: In this paper, an inkjet-printed circular-shaped monopole ultra-wideband (UWB) antenna with an inside-cut feed structure was implemented on a flexible polyethylene terephthalate (PET) substrate.
Abstract: In this article, an inkjet-printed circular-shaped monopole ultra-wideband (UWB) antenna with an inside-cut feed structure was implemented on a flexible polyethylene terephthalate (PET) substrate. The coplanar waveguide (CPW)-fed antenna was designed using ANSYS high-frequency structural simulator (HFSS), which operates at 3.04–10.70 GHz and 15.18–18 GHz (upper Ku band) with a return loss < −10 dB and a VSWR < 2. The antenna, with the dimensions of 47 mm × 25 mm × 0.135 mm, exhibited omnidirectional radiation characteristics over the entire impedance bandwidth, with an average peak gain of 3.94 dBi. The simulated antenna structure was in good agreement with the experiment’s measured results under flat and bending conditions, making it conducive for flexible and wearable Internet of things (IoT) applications.
TL;DR: Given the cost of microfabrication is reduced substantially with rapid technological advancements, the results of this letter suggest that high-speed THz communications can be realized for wide-scale applications.
Abstract: The microwave frequency band typically used for wireless communications will soon become saturated and will no longer be able to fulfill the high bandwidth demands of modern communication networks. Terahertz (THz) communication has appeared as a highly attractive, future-generation wireless technology that offers higher spectral bandwidth and, therefore, higher data rates. However, the full exploitation of THz technologies is contingent upon the availability of energy-efficient sources and devices. In this letter, we present a fabrication and measurement of a microscale planar inverted cone antenna array made of gold. Using an ungrounded coplanar waveguide (CPW) feed, the microfabricated structure provides a bandwidth of 37.9% with the resonant frequency of 0.925 THz. Given the cost of microfabrication is reduced substantially with rapid technological advancements, the results of this letter suggest that high-speed THz communications can be realized for wide-scale applications.
TL;DR: This proposed MIMO antenna design can be used for THz applications in future beyond the fifth generation (B5G) technology and is within acceptable limit over the entire THz frequency of operation.
TL;DR: In this article, a compact 8-state frequency reconfigurable ultra-wideband (UWB) monopole antenna is proposed, which consists of a coplanar waveguide structure, defected ground structure (DGS), rectangular radiation patch, and stepped feed line.
Abstract: To meet the anti-interference and multi-function requirements of the antenna, a compact 8-states frequency reconfigurable ultra-wideband (UWB) monopole antenna is proposed. The antenna consists of a coplanar waveguide structure (CPW), defected ground structure (DGS), rectangular radiation patch, and stepped feed line. Band rejections at the C band, WLAN, and X band are generated by two C-slots and inverted U-slot, respectively. Three PIN diodes are connected across the C-slots and inverted U-slot. By controlling the on/off state of PIN diodes to realize notch reconfiguration. The antenna size is only 22 mm $\times 13$ mm $\times0.8$ mm. The measured results show that the antenna can work in 8 states. The impedance bandwidth of UWB mode is 2.82-13.25 GHz, the relative bandwidth is 129.8%. The notch band is 3.19-4.58 GHz, 5.26-6.21 GHz, and 7.87-8.73 GHz, respectively. The antenna has stable gain, good omnidirectional radiation performance, and can switch freely between UWB mode and each notch band mode.
TL;DR: In this article, a new compact filtering power divider (FPD) on the square substrate integrated waveguide (SIW) with wideband isolation is proposed, which consists of the coplanar waveguide feeding line of Port 1, the capacitor, a resistor, and the square SIW cavity.
Abstract: In this letter, a new compact filtering power divider (FPD) on the square substrate integrated waveguide (SIW) with wideband isolation is proposed. As the isolation network is embedded in a square SIW cavity, good in-band isolation, compact structure, and low insertion loss can be simultaneously attained. The proposed FPD consists of the coplanar waveguide feeding line of Port 1, the capacitor, a resistor, and the square SIW cavity. TE101, TE201, and slot-line modes can realize third-order filtering response. Center frequency ( $f_{0}$ ) and bandwidth of the filtering response can be independently adjusted. In order to achieve out-of-band isolation, Port 2/3 is placed in the specific position to suppress the high-order modes according to the electric-field distributions of these modes. Finally, a prototype with in-band return loss of 20 dB across 5.59–6.4 GHz is designed at 5.99 GHz. The bandwidths of isolation higher than 21 dB and upper stopband attenuation higher than 20 dB are extended to $2.79f_{0}$ and $2.83f_{0}$ , respectively.
TL;DR: In this paper, a high-efficiency broadband mm-wave integrated power amplifier (PA) with a low-loss slotline-based power combing technique is proposed, which consists of grounded coplanar waveguide (GCPW)-to-slotline transitions and folded slots to simultaneously achieve power combining and impedance matching.
Abstract: In this article, a high-efficiency broadband millimeter-wave (mm-Wave) integrated power amplifier (PA) with a low-loss slotline-based power combing technique is proposed. The proposed slotline-based power combiner consists of grounded coplanar waveguide (GCPW)-to-slotline transitions and folded slots to simultaneously achieve power combining and impedance matching. This technique provides a broadband parallel-series combining method to enhance the output power of PAs at mm-Wave frequencies while maintaining the compact area and high efficiency. As a proof of concept, a compact four-to-one hybrid power combiner is implemented in a 130-nm SiGe BiCMOS back-end-of-line (BEOL) process, which leads to a small die area of 126 μm x 240 μm and a low measured insertion loss of 0.5 dB. The 3-dB bandwidth is over 80 GHz covering the whole G-band (140-220 GHz). Based on this structure, a high-efficiency mm-Wave PA has been fabricated in the 130-nm SiGe BiCMOS technology. The three-stage PA achieves a peak power gain of 30.7 dB, 3-dB small-signal gain bandwidth of 40 GHz from 142 to 182 GHz, a measured maximum saturated output power of 18.1 dBm, and a peak power-added efficiency (PAE) of 12.4% at 161 GHz. The extremely compact power combining methodology leads to a small core area of 488 μm x 214 μm and an output power per unit die area of 662 mW/mm².
TL;DR: A compact coplanar waveguide (CPW)-fed band-notched ultra wideband (UWB) multiple-input multiple-output (MIMO) flexible antenna on liquid crystal polymer (LCP) substrate is designed in this article.
Abstract: A compact coplanar waveguide (CPW)-fed band-notched ultra-wideband (UWB) multiple-input multiple-output (MIMO) flexible antenna on liquid crystal polymer (LCP) substrate is designed. It is composed...
TL;DR: In this article, an ultrawideband magnetic probe with high electric field suppression ratio (EFSR) was proposed, which has three parts: the loop part, the transmission part, and the head part.
Abstract: In this article, an ultrawideband magnetic probe with high electric field suppression ratio (EFSR) is proposed. The probe has three parts: the loop part, the transmission part, and the head part. Shield metal sheets are designed in the loop part to enhance EFSR. The tapered transmission line in the transmission part and the quasi coaxial transition in the head part are adopted for impedance matching between the induction loop and the grounded coplanar waveguide (GCPW) in the head part. Then, segmented resistance–inductance–capacitance ( RLC ) equivalent circuit models of the probe are proposed for magnetic field coupling and electric field coupling, which are suitable for accurate modeling and efficient optimization of the magnetic probe. In addition, the coupling capacitors between the shield metal sheets and the device under test (DUT) are extracted utilizing the conformal transforming method with analytical formulas. Finally, this magnetic probe is fabricated under printed circuit board (PCB) technology and used in measuring the magnetic field distribution. The measurement and simulation results agree well. The probe has a bandwidth of 100 MHz–30 GHz and an EFSR of higher than 21 dB. Compared with the conventional probe with similar bandwidth, the proposed probe can improve the EFSR by 9 dB.