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Showing papers on "Coplanar waveguide published in 2022"


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
01 Feb 2022-Sensors
TL;DR: The proposed metamaterial (MTM)-based directional coplanar waveguide-fed reconfigurable textile antenna using radiofrequency (RF) varactor diodes for microwave breast imaging may be used clinically for the detection of breast cancer.
Abstract: In this paper, we report the design and development of a metamaterial (MTM)-based directional coplanar waveguide (CPW)-fed reconfigurable textile antenna using radiofrequency (RF) varactor diodes for microwave breast imaging. Both simulation and measurement results of the proposed MTM-based CPW-fed reconfigurable textile antenna revealed a continuous frequency reconfiguration to a distinct frequency band between 2.42 GHz and 3.2 GHz with a frequency ratio of 2.33:1, and with a static bandwidth at 4–15 GHz. The results also indicated that directional radiation pattern could be produced at the frequency reconfigurable region and the antenna had a peak gain of 7.56 dBi with an average efficiency of more than 67%. The MTM-based reconfigurable antenna was also tested under the deformed condition and analysed in the vicinity of the breast phantom. This microwave imaging system was used to perform simulation and measurement experiments on a custom-fabricated realistic breast phantom with heterogeneous tissue composition with image reconstruction using delay-and-sum (DAS) and delay-multiply-and-sum (DMAS) algorithms. Given that the MWI system was capable of detecting a cancer as small as 10 mm in the breast phantom, we propose that this technique may be used clinically for the detection of breast cancer.

16 citations


Journal ArticleDOI
TL;DR: In this article , a coplanar waveguide (CPW) fed flexible interconnected 4-port MIMO antenna is proposed for UWB, X, and Ku band applications.
Abstract: A coplanar waveguide (CPW) fed flexible interconnected 4-port MIMO antenna is proposed for UWB, X, and Ku band applications having a size $0.67\lambda \times 0.81\lambda \times 0.0028\lambda $ (at 3.58 GHz). The antenna parameters are characterized by using sets of real measurements to validate the antenna design and modelling. A precise milling machine is used for fabricating the single and 4-port antennas over a flexible FR-4 Substrate. Vector network analyser (VNA) is used for measuring scattering and transmission coefficients. As well as, a shielded anechoic chamber is utilised for measuring the far field radiations and the gain of the antenna under test (AUT). The basic antenna that is a part of the 4-port structure consists of a CPW fed octagonal structure surrounded by an octagonal-shaped slot. The MIMO ability is achieved by arranging the 4 identical elements symmetrically in a successive rotational means for achieving good polarization diversity. The connected ground between the elements is achieved by introducing a plus-shaped slotted structure separated by a slotted diamond at the center in the 4-port structure. None of the slots touches each other thus ensuring the common reference while maintaining the inter-element isolation better than 15 dB. The antenna demonstrated maximum gain and minimum efficiency of 6.8 dBi and 89%, respectively besides attaining a 10-dB impedance bandwidth of 125.83% (3.89-17.09 GHz) and envelope correlation coefficient (ECC) < 0.02. Finally, the 4-port flexible antenna is tested in terms of S parameters and ECC under bending conditions along the X and Y axis followed by a time-domain analysis that exhibited very good performance.

14 citations


Journal ArticleDOI
TL;DR: In this article , a compact Coplanar Waveguide (CPW) fed connected ground multiple-input-multiple-output (MIMO) antennas operating in the sub-millimeter-wave 5G New Radio (NR) n257/n258/n261 bands are presented.
Abstract: This paper embodies the design and development of a compact Coplanar Waveguide (CPW) fed connected ground Multiple- Input-Multiple-Output (MIMO) antennas operating in the sub-millimeter-wave 5G New Radio (NR) n257/n258/n261 bands. The planar geometry leads to a small and compact structure while achieving a wide operating bandwidth, high gain, and better radiation efficiency. The top surface of the antenna comprises a modified CPW in the form of two circular structures that feeds the centrally slotted circular patch. The single antenna structure is arranged in a rotational orthogonal manner forming a 4-port structure. The ground plane on the bottom of a 4-port structure is connected using a circular ring which is carefully optimized for achieving isolation levels>20 dB across the band of interest. The sub-mm-wave resonating 4-port antenna achieves a compact size of 24 × 24 mm2, a wide bandwidth of 24.8–44.45 GHz (79.35%), the maximum gain of 8.6dBi, and minimum efficiency of 85% across the bands of interest. The proposed antenna element is fabricated over Rogers 5880 substrate and experimental tests are carried out, where a good correlation between the scattering parameters, transmission parameters, gain, and MIMO diversity performance is achieved that makes the antenna a potential candidate for its application in sub-millimeter wave 5G applications.

11 citations


Journal ArticleDOI
TL;DR: In this paper , a reflective mode displacement sensor is designed based on the resonance frequency shift, where the linearity of the sensor is enhanced using a tapered metallic patch that forms the capacitance of the sensors, leading to a better dynamic range.
Abstract: A wide dynamic range reflective mode displacement sensor is designed in this article based on the resonance frequency shift. The linearity of the sensor is enhanced using a tapered metallic patch that forms the capacitance of the sensor, leading to a better dynamic range. The sensor is designed using a coplanar waveguide (CPW) terminated with a series $RLC$ resonator with $R=50\,\,\Omega $ . A movable dielectric slab is placed above the capacitive patch of the resonator, where displacing the dielectric slab modifies the overall capacitance of the resonator causing a shift in the resonance frequency. The sensing principle is analyzed in detail, using an accurate circuit model and full-wave electromagnetic simulations. The proposed sensing method is capable of detecting the displacement direction. Furthermore, the sensing concept can be extended to a 2-D displacement sensor as well. The sensing approach and the design concept are verified through the fabrication and measurement of a sensor prototype.

10 citations


Journal ArticleDOI
TL;DR: In this paper , a gated Cooper-pair box, coupled to two superconducting coplanar waveguide resonators with different frequencies, was constructed to demonstrate the strong coupling of a charge qubit to two Superconducting resonators, with the ability to perform voltage driving of the qubit at GHz frequencies.
Abstract: Superconducting circuits present a promising platform with which to realize a quantum refrigerator. Motivated by this, we fabricate and perform spectroscopy of a gated Cooper-pair box, capacitively coupled to two superconducting coplanar waveguide resonators with different frequencies. We experimentally demonstrate the strong coupling of a charge qubit to two superconducting resonators, with the ability to perform voltage driving of the qubit at GHz frequencies. We go on to discuss how the measured device could be modified to operate as a cyclic quantum refrigerator by terminating the resonators with normal-metal resistors acting as heat baths.

9 citations


Journal ArticleDOI
TL;DR: In this article , a planar monopole antenna operating in 3.1 GHz and 10.8 GHz is designed on a FR-4 substrate and the overall size of the antenna is 12.5 mm.
Abstract: Ultra-Wideband (UWB) is a wireless communication technology that can be utilized for precise indoor positioning system. UWB is low power-consuming and resistant to complex multipath environments, thanks to a short pulse signal. Since the main desired characteristics of the UWB antennas for radio-frequency localization systems are wide bandwidth, omnidirectional radiation pattern, and low profile for simple integration with printed circuit boards, various planar monopole antennas for UWB applications were proposed to meet the requirements. In order to satisfy these conditions, in this paper, a novel compact UWB planar monopole antenna operating in 3.1 GHz – 10.8 GHz is designed on FR-4 substrate. The overall size of the antenna is 12.5 × 12.5 × 1 mm3, which is 0.129 λ0 × 0.258 λ0 × 0.01 λ0 in free space at the lowest frequency. The transmission line is designed based on a coplanar waveguide with ground (CPWG) and vias in the CPWG are employed to eliminate non-radiating phenomenon at some specific frequencies. The shape of the radiator is modified from the hexagonal shape and a ribbon-shaped slot inside the radiator is adapted to improve the operating frequency range. The proposed UWB planar monopole antenna is fabricated and measured. The proposed antenna provides good antenna performance from 3.1 to 10.8 GHz and also the radiation patterns at various frequencies are omnidirectional pattern.

9 citations


Journal ArticleDOI
TL;DR: In this paper , a single-frequency reflective-mode phase-variation microwave sensor devoted to the dielectric characterization of materials is presented, which is implemented in coplanar waveguide (CPW) technology and consists of two parts: (i) the sensing region, a step-impedance resonator (SIR) as termination of a CPW transmission line, and (ii) a cascade of high/low impedance quarter-wavelength inverters, used to boost up the sensitivity.
Abstract: This paper presents a single-frequency reflective-mode phase-variation microwave sensor devoted to the dielectric characterization of materials. The device is implemented in coplanar waveguide (CPW) technology and consists of two parts: (i) the sensing region, a step-impedance resonator (SIR) as termination of a CPW transmission line, and (ii) the design region, a cascade of high/low impedance quarter-wavelength inverters, used to boost up the sensitivity. By placing the so-called material under test (MUT) on top of the sensing region, the capacitance of the SIR is altered due to the effects of the dielectric constant of the MUT. This modifies the phase of the reflection coefficient seen from the input port, the output variable. From a circuit analysis, it is demonstrated that the sensitivity for small perturbations in the vicinity of the dielectric constant of a reference (REF) material can be optimized by setting the operation frequency of the sensor to the resonance frequency of the SIR loaded with such REF material. The maximum sensitivity in one of the reported sensors is as high as 66.5°, and the main figure of merit, defined as the ratio between the maximum sensitivity and the area of the sensing region expressed in terms of the squared guided wavelength, is FoM = 3643°/λ2. Such figure of merit represents a significant improvement as compared to the one of the equivalent sensor implemented by means of an open-ended quarter-wavelength sensing line. Such equivalence between the semi-lumped element (i.e., SIR-based) sensor and the fully distributed counterpart is also analyzed in the paper.

8 citations


Journal ArticleDOI
TL;DR: In this article, a band-pass filter based on coplanar-waveguide and spoof surface plasmon polaritons (SSPPs) is proposed, which can operate from 0.65 THz to 2.02 THz with high efficiency and compact size.
Abstract: A THz ultra-broadband band-pass filter based on coplanar-waveguide and spoof surface plasmon polaritons (SSPPs) is proposed, which can be operated from 0.65 THz to 2.02 THz with high efficiency and compact size. Additionally, the lower and upper cut-off frequencies of the proposed filter can be controlled independently by changing the corresponding parameters. The interdigital structure is used to filter the low frequency wave, meanwhile, the SSPPs is designed for producing the upper cut-off frequency. The operating principles are explained by dispersion curves and field distributions. The return loss and insertion loss of the proposed filter are higher than 11 dB and less than 2 dB in the passband, respectively. For validating the proposed band-pass filter design concept, a prototype of a filter operating at millimeter-wave frequency is fabricated and measured, and the measured results have a good agreement with the simulated ones.

7 citations


Journal ArticleDOI
TL;DR: In this paper , a compact circularly polarized (CP) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA), where a ring patch with a gap and two arc-shaped metallic stubs as the radiator is analyzed and optimized by CMA to figure out the orthogonal modes and operating frequency band for potential good axial ratio (AR) performance.
Abstract: A compact circularly polarized (CP) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA). A ring patch with a gap and two arc-shaped metallic stubs as the radiator is analyzed and optimized by CMA to figure out the orthogonal modes and operating frequency band for potential good axial ratio (AR) performance. The studies of these CP modes provide a physical insight into the property of broadband circular polarization. Such an in-depth understanding paves the way for the proposal of novel CP antenna with separation between the design of radiator and feeding network. A 50-Ω coplanar waveguide (CPW) is introduced and placed appropriately to excite the desired modes based on the information from CMA, which employs two asymmetric ground planes to improve the performance in terms of AR and impedance matching. The antenna with a compact size of 0.71λ0 × 0.76λ0 × 0.038λ0 (λ0 is the free-space wavelength at the center frequency of the 3-dB AR bandwidth) is fabricated and measured for validation. The realized gain varies from 1.6 to 3.1 dBic over the operating bandwidth characterized by the measured 10-dB impedance bandwidth of 83.8% (3.98–9.72 GHz) and 3-dB AR bandwidth of 70.3% (4.59–9.57 GHz), respectively.

7 citations


Journal ArticleDOI
TL;DR: In this article , a novel high isolation and high capacitance-ratio radio-frequency micro-electromechanical systems (RF MEMS) switch working at Ka-band is designed, fabricated, measured and analyzed.
Abstract: In this paper, a novel high isolation and high-capacitance-ratio radio-frequency micro-electromechanical systems (RF MEMS) switch working at Ka-band is designed, fabricated, measured and analyzed. The proposed RF MEMS switch mainly consists of a MEMS metallic beam, coplanar waveguide (CPW) transmission line, dielectric layer and metal–insulator–metal (MIM) fixed capacitors. The measured results indicate that the insertion loss is better than 0.5 dB at 32 GHz, and the isolation is more than 35 dB at the resonant frequency. From the fitted results, the capacitance ratio is 246.3. Compared with traditional MEMS capacitive switches, this proposed MEMS switch exhibits a high capacitance ratio and provides a wonderful solution for cutting-edge performance in 5G and other high-performance applications.


Journal ArticleDOI
01 Jul 2022-Sensors
TL;DR: In this article , a compact multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) that is suitable for internet of things (IoT) sensor networks is proposed with reduced coupling between elements.
Abstract: A compact multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) that is suitable for internet of things (IoT) sensor networks is proposed with reduced coupling between elements. Two rectangular-shaped DRAs have been placed on the opposite sides of a Rogers substrate and each is fed using a coplanar waveguide (CPW) feed with slots etched in a dedicated metal ground plane that is located under the DRA. Moreover, locating the elements at the opposite sides of the substrate has improved the isolation by 27 dB without the need to incorporate additional complex structures, which has reduced the overall antenna size. Furthermore, a dual band operation is achieved since each antenna resonates at two frequencies: 28 GHz and 38 GHz with respective impedance matching bandwidths of 18% and 13%. As a result, the corresponding data rates are also increased independently. In addition to the advantages of improved isolation, compact size and dual band operation, the proposed configuration offers a diversity gain (DG), envelope correlation coefficient (ECC) and channel capacity loss (CCL) of 9.98 dB, 0.007, 0.06 bits/s/Hz over the desired bands, respectively. A prototype has been built with good agreement between simulated and measured results.

Journal ArticleDOI
TL;DR: In this paper , a novel capacitive power sensor based on double MEMS cantilever beams is proposed, which is designed and fabricated using GaAs MMIC process and MEMS technology.
Abstract: In order to improve the sensitivity characteristic and the fabrication reliability, a novel capacitive power sensor based on double MEMS cantilever beams is proposed in this work. It is designed and fabricated using GaAs MMIC process and MEMS technology. A lumped circuit model is built to study the microwave characteristic of this capacitive microwave power sensor. The influence of impedance value and electric length of the coplanar waveguide on the microwave performance of the double MEMS beams are studied. The microwave characteristic of both ports are measured. The return loss of port A is from −11.5dB to −14.6dB, and the return loss of port B is from −12.1dB to −14.3dB at 8-12GHz. The insertion loss of port A is from −3.6 dB to −2.8dB, and the insertion loss of port B is from −3.7 dB to −2.9dB at 8-12GHz. The measured results show that this capacitive power sensor has a good microwave characteristic. The measured sensitivity of this capacitive microwave power sensor is about 51.6 fF/W @10 GHz, and the theoretical sensitivity is 55.97 fF/W. The relative error is 7.8%. Compared with the capacitive microwave power detection system based on single cantilever beam, the sensitivity characteristics have been greatly improved. It is valuable to realize the multiple beams detection technology and enable further interesting possibilities in the field of microwave power detection.


Journal ArticleDOI
TL;DR: In this article , a broadband circularly polarized composite right/left-hand (CRLH) antenna is presented, where a compact microstrip line inductor and an interdigital capacitor are used to form a left-handed parallel inductor, and a series capacitor is optimized.
Abstract: This article presents a broadband circularly polarized composite right/left-hand (CRLH) antenna. A compact microstrip line inductor and an interdigital capacitor are used to form a left-handed parallel inductor and a left-handed series capacitor. The metamaterial parameters of the series inductor and the parallel inductor are optimized. The asymmetric perturbation is introduced to excite the circularly polarized (CP) electromagnetic wave. The influence of interdigital capacitance on the electrical performance of the antenna is analyzed theoretically and experimentally. The value of CL is changed to reduce the electrical size of the antenna, and the resonant frequency of the antenna is reduced accordingly. The physical dimensions of this CPW-Fed monopole antenna are 25 mm ∗ 24 mm ∗ 1 mm. The measured 10 dB wide impedance bandwidth is 79.5%, and the measured 3 dB axial ratio (AR) bandwidth is 56.2%.

Journal ArticleDOI
TL;DR: In this article , a coplanar waveguide (CPW)-fed triple-band flexible antenna operating at 5, 5.8, and 6.6 GHz for wireless local area network (WLAN) and WBAN applications is presented.
Abstract: This article presents a $50\times40$ mm2 coplanar waveguide (CPW)-fed triple-band flexible antenna operating at 5, 5.8, and 6.6 GHz for wireless local area network (WLAN) and wireless body area network (WBAN) applications. In the proposed design, polydimethylsiloxane (PDMS) is used as a substrate with a dielectric constant $\varepsilon _{r}$ of 2.65 and a loss tangent tan $\delta _{\varepsilon r}$ of 0.02. In addition to the rectangular slot on the ground, the presented antenna has a single circular split-ring resonator (SRR) structure on the same side of the patch. This provides the required frequency notched characteristics for the targeted frequency bands, compactness, minimize losses, and backward radiation when used in close proximity to the human body. The proposed flexible antenna provides stable results in terms of performance parameters and specific absorption rate (SAR). We have also investigated the antenna under different operating conditions of moisture and bending. There exists a strong correlation between the simulation and measured findings.

Proceedings ArticleDOI
27 Mar 2022
TL;DR: In this paper , an ultra-wideband (UWB) compact size printed monopole antenna with improved gain and efficiency is presented, which contains a cup-shaped radiator fed by a coplanar waveguide (CPW) technique.
Abstract: This paper presents an ultra-wideband (UWB) compact size printed monopole antenna with improved gain and efficiency. This broadband printed monopole antenna contains a cup-shaped radiator fed by a coplanar waveguide (CPW) technique. The designed UWB antenna is fabricated on a less-priced FR-4 substrate with relative permittivity of 4.3, loss tangent of 0.025, and a standard height of 1.6 mm, sized at 31.68 mm $\times 23.76$ mm $\times 1.6$ mm suitable for wireless communication system. The designed UWB antenna works with maximum gain (peak gain of 4.1 dB) across the whole UWB spectrum 3–11 GHz. The $S_{11}$ results are simulated and measured, and the results are debated in detail.

Journal ArticleDOI
TL;DR: In this article , the authors designed and fabricated aluminum film quarter-wavelength coplanar waveguide (CPW) resonators on sapphire substrates for solid-state quantum computation and single-photon detection.
Abstract: The coplanar waveguide (CPW) microwave resonators have been widely applied for solid-state quantum computation and single-photon detection. Based on the physical analysis for the high fidelity readouts of the qubit(s), in this paper we design and then fabricate accordingly the desired aluminum (Al) film quarter-wavelength resonators on sapphire substrates. The ultra-low temperature measurement results show that the linearity of the internal quality factor under the proper driving power is satisfied well for the high fidelity readouts of the qubit(s); and the phase- and amplitude fractional frequency noises are significantly less for avoiding the potential information false alarms of the detected qubit during the readouts. With the demonstrated qubit-resonator experimental parameters, we argue that the designed and fabricated quarter-wavelength CPW resonators, with optimized parameters, can be used to implement the desired weakly perturbing readout measurements of the solid-state qubits on-chip.

Journal ArticleDOI
TL;DR: In this article , the authors examined the |S 11| parameter of a multiband Coplanar Waveguide (CPW)-fed antenna and proposed Ant.1 and Ant.2.
Abstract:

This article aims to examine the |S11| parameter of a multiband Coplanar Waveguide (CPW)-fed antenna. The proposed square-shaped antenna-1 (Ant.1) and antenna-2 (Ant. 2) are primarily composed of three ground terminal stubs: Terminal-1 (T1), Terminal-2 (T2), and Terminal-3 (T3), all of which have an inverted L-shaped radiating patch. The proposed antennas' resonance frequencies (fr) can be adjusted by the electrical dimension and length of the stub resonators, the dielectric constant (εr) of substrate materials, and their appropriate thicknesses. It will have an impact on their return loss (|S11|), Impedance Bandwidth (IBW), radiation pattern, and antenna performance in terms of frequency characteristics, as demonstrated in this article. The proposed structure based on Flame-Retardant fiber glass epoxy (FR4) substrate covered a wideband frequency range from 1.5 to 3.2 GHz, (IBW = 1.7 GHz) and from 3.4 to 3.65 GHz (IBW = 0.25 GHz). The total IBW is 1.95 GHz, at S11 ≤ −10 dB with three resonance frequencies of values fr1 = 1.75, fr2 = 2.65, and fr3 = 3.50 GHz) for triple-band applications. The results are compared with the research work reported earlier. The proposed Ant.1 ensured, dual and triple band applications whereas the proposed Ant. 2 ensured dual, triple and quad bands applications with reasonable antennas' sizes similar to the earlier reported works. Furthermore, the design technique as well as the impacts of various substrate materials and multi-stub resonator lengths on the operating bands and resonance frequency are thoroughly explored and analyzed.


Journal ArticleDOI
TL;DR: In this article , a multilayer self-packaged suspended coplanar waveguide (SCPW) leaf-shaped wide slot wideband filtenna is proposed by using leafshaped feeding source and three-line couplings.
Abstract: In this letter, a multilayer self-packaged suspended coplanar waveguide (SCPW) leaf-shaped wide slot wideband filtenna is proposed by using leaf-shaped feeding source and three-line couplings. The filtenna is designed working at 3.2 GHz with a fractional bandwidth of 52.3% and a gain of 4.02 dBi, and a pair of gain zeros which are used for improving frequency selectivity and suppressing the out-of-band spurious harmonics have been realized because of the introduced filtering circuit. The proposed filtenna has been fabricated and measured, and the experimental results approach to the predictions, while the advantages of wide bandwidth, high gain flatness, high frequency selectivity, and stable radiation pattern have been demonstrated.

Book ChapterDOI
TL;DR: In this paper , the authors proposed a compact and efficient CPW-Fed ultra-wideband (UWB) antenna suitable for integration in microwave imaging systems for early detection of breast cancer.
Abstract: The purpose of this research work is to propose a compact and efficient CPW-Fed ultra-wideband (UWB) antenna suitable for integration in microwave imaging systems for early detection of breast cancer. The suggested structure consists of a coplanar waveguide monopole UWB antenna printed on Isola substrate of volume 44 $$\times $$ 38 $$\times $$ 0.762 mm3. The designed structure is simulated and analyzed using both CST Microwave Studio® and ANSYS HFSS EM simulation software. The Simulation results show frequency band coverage from 1.48 to 17.20 GHz, having a large impedance bandwidth of 15.72 GHz. A prototype of the antenna is fabricated and tested with a network analyzer. The experimental result confirms the large UWB resonance expanding from 1.87 to 16.23 GHz for VSWR < 2. Moreover, the antenna exhibits good gain characteristics with a maximum value of about 6.5 dBi at 11.42 GHz accompanying stable and bidirectional radiation patterns. The miniaturized size and low cost of the antenna may contribute to reduce the size and mainly the high cost of breast cancer system detection which could help in turn to make it available on a large scale.

Journal ArticleDOI
11 Jul 2022-Frequenz
TL;DR: In this article , a graphene-based antenna array for terahertz (THz) applications was proposed, which has four radiating square shaped patches fed by a coplanar waveguide (CPW) technique.
Abstract: Abstract This paper presents a graphene-based antenna array for terahertz (THz) applications. The suggested antenna array has four radiating square shaped patches fed by a coplanar waveguide (CPW) technique. The proposed antenna array operates at the three frequencies with operational bandwidths of 1.173–1.210 THz (at 1.19 THz), 1.270–1.320 THz (at 1.3 GHz), and 1.368–1.346 THz (at 1.4 GHz). The total area of the antenna array is reported as 1000 × 1000 µm2, printed on a Silicon substrate with a thickness of 20 µm and a dielectric constant of ϵ r = 11.9. To enhance the structure’s performance and optimize the feeding network, a parametric analysis was performed using the FDTD technique. Furthermore, the key properties of the proposed antenna array, such as resonance frequency, peak gain, and radiation efficiency, may be changed by adjusting the chemical potentials of the graphene in the antenna array. The use of graphene’s chemical potential tuneability yields exceptional results comparing to the recent research outputs, with a peak gain and radiation efficiency of 10.45 dB and 70%, respectively. These results show the performance of the suggested design for constructing antenna arrays for use in THz applications.

Proceedings ArticleDOI
27 Mar 2022
TL;DR: In this paper , two miniaturized substrate integrated waveguide (SIW) cavity-backed slot antennas (CBSAs) with multiband and broadband characteristics are presented, where the first antenna combines the modified non-resonant rectangular slot with two pairs of symmetrically placed shorting pins and fed with tapered coplanar waveguide to SIW transition for obtaining three resonances at 8.8, 12.25, and 14.35 GHz.
Abstract: This paper presents two novel miniaturized substrate integrated waveguide (SIW) cavity-backed slot antennas (CBSAs) with multiband and broadband characteristics. The first antenna combines the modified non-resonant rectangular slot with two pairs of symmetrically placed shorting pins and fed with tapered coplanar waveguide (CPW) to SIW transition for obtaining three resonances at 8.8, 12.25, and 14.35 GHz. The 10 dB return loss bandwidths (BWs) correspond to three resonances are 4.78, 3.11, and 1.82 % with peak realized gain of 6.41, 6.31, and 7.26 dBi respectively. Later for the second antenna, an indigenous method of splitting the SIW cavity is incorporated using shorting vias to obtain broadband impedance matching. Lower and high order modes (half TE110 and TE210) of the SIW cavity are coupled together to achieve broad BW with S11 < -10 dB from 12.34 - 14.54 GHz (16.4 %) and a flat gain > 6.4 dBi over the operating range.

Journal ArticleDOI
28 Jul 2022-Sensors
TL;DR: In this article , a dual-band graphene coplanar waveguide antenna is designed for smart cities and internet of things applications, which is based on two trapezoidal patches that generate the dualband behavior.
Abstract: In this paper, a dual-band graphene coplanar waveguide antenna is designed for smart cities and internet of things applications. A graphene film is chosen as the conductive material for the radiation patches and ground plane with a thickness of 240 μm and an electric conductivity of 3.5 × 105 S/m. The dielectric is glass with a dielectric permittivity of 6 and a thickness of 2 mm. The implementation of the antenna on glass permits the integration of the antenna in smart cities and IoT applications. This antenna is based on two trapezoidal patches that generate the dual-band behavior. The overall dimensions of the antenna are 30 mm × 30 mm × 2 mm. The reflection coefficient, gain, and radiation patterns were measured and compared with the simulations. The antenna covers two frequency bands; the lower band covers the 2.45 GHz ISM band, and the upper band range covers from 4 to 7 GHz.

Journal ArticleDOI
TL;DR: In this paper , the authors presented an optically subharmonic pumped WR3-mixer for enabling photonic coherent frequency-domain terahertz imaging and spectroscopy systems in the future.
Abstract: In this work, we present an optically subharmonic pumped WR3-mixer for enabling photonic coherent frequency-domain terahertz (THz) imaging and spectroscopy systems in the future. The studied mixer operates within the upper range of the WR3-band from 270 GHz to 320 GHz. High-power uni-travelling carrier photodiodes (UTC-PDs) are developed for providing the subharmonic local oscillator (LO) signal within the corresponding WR6-band in the range between 135 GHz and 160 GHz. The proposed THz mixer module consists of a gallium arsenide (GaAs)-based low barrier Schottky diodes (LBSDs) chip and an indium phosphide (InP)-based UTC-PD chip. For integrating the UTC-PD with the WR6 at the mixer's LO input, an E-plane transition and a stepped-impedance microstrip line low pass filter (MSL-LPF) are developed and monolithically integrated with the UTC-PD chip on a 100 µm thick InP substrate. The E-plane transition converts the quasi-TEM mode of the grounded coplanar waveguide (GCPW) to the dominant TE10 mode of the WR6 and matches the GCPW's impedance with the WR6's impedance. According to full-wave EM simulations, the transition exhibits a 1 dB bandwidth (BW) of more than 30 GHz (138.8-172.1 GHz) with a corresponding return loss (RL) better than 10 dB, whereas the minimum insertion loss (IL) is 0.65 dB at a frequency of 150 GHz. Experimentally, the 1 dB BW of the fabricated transition is found to be between 140 GHz and 170 GHz, which confirms the numerical results. The minimum measured IL is 2.94 dB, i.e., about 2 dB larger than the simulated value. In order to achieve the required LO power for successfully pumping the mixer in a direct approach (i.e., without an additional LO amplifier), the design of the epitaxial system of the UTC-PD is optimized to provide a high output power within the WR6-band (110-170 GHz). Experimentally, at 150 GHz, the output power of the fabricated UTC-PD chip is measured to be +3.38 dBm at a photocurrent of 21 mA. To our knowledge, this is the highest output power ever achieved from a UTC-PD at 150 GHz. Finally, the developed high-power UTC-PDs are used as LO source to pump the subharmonic WR3-mixer. Experimentally, the conversion loss (CL) is determined in dependency of the LO power levels within the RF frequency range between 271 GHz and 321 GHz for a fixed IF at 1 GHz. The achieved results have revealed an inverse relation between the CL and LO power level, where the average minimum CL of 16.8 dB is achieved at the highest applied LO power level, corresponding to a photocurrent of 10 mA. This CL figure is promising and is expected to reach the CL of electronically pumped and commercially available THz mixers (∼12 dB) after packaging the LO source with the mixer. Furthermore, an average CL of 17.2 dB is measured at a fixed LO frequency of 150 GHz and a tuned RF frequency between 301 GHz and 310 GHz, i.e., IF between 1 GHz and 10 GHz.

Journal ArticleDOI
TL;DR: In this article , a gate-tunable kinetic inductance in a hybrid nanowire was detected by embedding it into a quarter-wave coplanar waveguide resonator and measuring the resonance frequency.
Abstract: We report the detection of a gate-tunable kinetic inductance in a hybrid $\mathrm{In}\mathrm{As}$/$\mathrm{Al}$ nanowire. For this purpose, we embed the nanowire into a quarter-wave coplanar waveguide resonator and measure the resonance frequency of the circuit. We find that the resonance frequency can be changed via the gate voltage that controls the electron density of the proximitized semiconductor and thus the nanowire inductance. Applying Mattis-Bardeen theory, we extract the gate dependence of the normal-state conductivity of the nanowire, as well as its superconducting gap. Our measurements complement existing characterization methods for hybrid nanowires and provide a useful tool for gate-controlled superconducting electronics.

Journal ArticleDOI
TL;DR: In this paper , a coplanar waveguide (CPW) was used to suppress SRE contribution to inverse spin Hall effect (ISHE) voltage signal, and the results showed that the sign and size of the measured transverse voltage signal depends on the width of the sample along the CPW active line.
Abstract: Spin pumping (SP) is a well-established method to generate pure spin currents allowing efficient spin injection into metals and semiconductors avoiding the problem of impedance mismatch. However, to disentangle pure spin currents from parasitic effects due to spin rectification effects (SRE) is a difficult task that is seriously hampering further developments. Here we propose a simple method that allows suppressing SRE contribution to inverse spin Hall effect (ISHE) voltage signal avoiding long and tedious angle-dependent measurements. We show an experimental study in the well-known Py/Pt system by using a coplanar waveguide (CPW). Results obtained demonstrate that the sign and size of the measured transverse voltage signal depends on the width of the sample along the CPW active line. A progressive reduction of this width evidences that SRE contribution to the measured transverse voltage signal becomes negligibly small for sample width below 200 μm. A numerical solution of the Maxwell equations in the CPW-sample setup, by using the Landau-Lifshitz equation with the Gilbert damping term (LLG) as the constitutive equation of the media, and with the proper set of boundary conditions, confirms the obtained experimental results.

Journal ArticleDOI
27 Dec 2022-Sensors
TL;DR: In this article , an inverted microstrip Gap Waveguide filtering antenna integrated with two stopband filters is proposed to simultaneously provide filtering and radiating functions, using the direct integration approach to cascade two periodic sets of coplanar coupled EBG resonators with a slot antenna.
Abstract: A new simple design of an inverted microstrip Gap Waveguide filtering antenna integrated with two stopband filters is proposed in this work. In order to simultaneously provide filtering and radiating functions, we use the direct integration approach to cascade two periodic sets of coplanar coupled EBG resonators with a slot antenna. The analysis shows that the filters can be easily adjusted in the same feeding layer of the antenna, without extra circuitry and without modifying the lines. EBG-filters are compact and offer great flexibility in determining the frequency, width and selectivity of the rejected bands. Experimental results for an X-band filtering antenna prototype are provided showing a 7.3% transmission band centered at 10.2 GHz and a realized gain peak of 2.1 dBi. The measurements demonstrate the filtering capability of the proposed antenna, achieving rejection levels greater than 12 dB and 20 dB for the bands below and above the operation band. The proposed low-complexity design offers good performance as a filter and as an antenna, showing the essential advantages of the Gap Waveguide Technology, including low losses, self-packaging and limited cost. This work demonstrates the possibility of integrating the new coplanar EBG-filters into future Gap Waveguide antenna designs to avoid unwanted radiation, to reduce interfering signals or to provide high isolation in multiband systems.

Journal ArticleDOI
01 May 2022
TL;DR: In this article , a transition from conductor-backed coplanar waveguide (CB-CPW) with substrate-integrated coaxial line (SICL) to substrate integrated waveguide was designed for the C-band frequency range.
Abstract: This brief describes a transition from conductor-backed-coplanar waveguide (CB-CPW) with substrate-integrated coaxial line (SICL) to substrate integrated waveguide (SIW). The transition is designed for the C-band frequency range. The CB-CPW slot lines play the main role in widening the bandwidth. These CPW slot lines are providing excitation of both even and odd mode waves in SIW, which improves the impedance bandwidth. Using the proposed concept, the measured single-mode fractional impedance bandwidth of 63.34%, the minimum insertion loss of 0.16 dB, and the overall loss below 25% are achieved. The simulated results are found to be in good agreement with the experimental ones obtained for the prototype developed in the laboratory.