Showing papers on "Return loss published in 2022"

60-GHz third-order on-chip bandpass filter using GaAs pHEMT technology

Abstract: A 60 GHz third-order on-chip bandpass filter (BPF) based on half-mode substrate integrated waveguide (HMSIW) cavity is synthesized using GaAs pHEMT technology. Two coupling slots are etched to divide the HMSIW cavity into three resonators, and then a third-order Chebyshev BPF is designed with predicted transmission zero, return loss and bandwidth through the synthesis method. The theoretical and extracted external quality factor and coupling coefficients are used to determine the dimensions of the BPF. For demonstration, a BPF sample with a bandwidth of 29.2% is fabricated, and its simulations and measurements are in good agreement.

High-Gain Dual-Band Dual-Sense Circularly Polarized Spiral Series-Fed Patch Antenna

Abstract: This paper demonstrates a dual-band circularly polarized (CP) two-dimensional (2D) series-fed patch array antenna. The CP rotating sense in each band is opposite to each other, which makes them well-suited for the downlink and uplink in satellite applications. The antenna can be designed to achieve a very high gain with a simple feeding structure using spiral microsip line, which can be integrated on a single-layered substrate. A theoretical framework for this type of antennas has been developed, which facilitates an efficient and fast design procedure requiring minimal computational resource. A prototype has been fabricated and measured, showing operating bandwidths (overlapped 10-dB return loss, 3-dB gain, 3-dB axial ratio bandwidths) of about 7% and 5%, realized broadside gains of 21.5 and 22 dBic at 12 and 14 GHz bands, respectively. This is an outstanding performance considering that the antenna profile is only 0.03 free-space wavelength (at 12 GHz) and the ratio between two operating frequencies is very tight accounting to only 1.17.

Design of Microstrip Patch Antenna for 5G Applications

Abstract: Millimeter-wave wireless technology (mmWave) has become a part of human life for fast and secure data transmission. This document introduces a 37GHz resonant frequency square microstrip patch antenna for mm Wave wireless communication. The antenna was designed and tested on a Rogers RT5880 board with a relative permittivity of 2.2 and a loss factor of 0.0009. Uses electromagnetic simulation software High Frequency Structure Simulator. The result of this paper shows minimal return loss -0.0812 dB, gain -1.205 dB, and impedance bandwidth 16.22% at 37 GHz resonant frequency. The voltage standing wave ratio (VSWR), radiation pattern has also presented for the proposed antenna which can be strong candidate for 5G mmWave cellular communication.

A Low Profile Frequency Reconfigurable Antenna for mmWave Applications

Abstract: A compact frequency reconfigurable printed antenna for millimeter-wave applications is presented in this paper. This design is obtained by the merging of a half-arc and a right-angled triangle patch extracted from a rectangular radiator. The design approach is based on the use of two S-PIN diodes to obtain frequency reconfigurability. The antenna exhibits seven reconfigurable bands while showing good performances in terms of return loss, bandwidth and gain. The proposed antenna is well suited for future fifth-generation (5G) networks because of its notable features of small overall size (7.5 \(\times\) 5 \(\times\) 0.762 mm3), wide bandwidth, and frequency reconfigurability.

Study of Microstrip Patch Antenna for Wireless Communication System

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.

An Isolated Out-of-Phase 3-dB Power Divider via Waveguide-to-Microstrip Transition

Abstract: In this letter, we present a 3-dB power divider with isolated port. The input port is a rectangular waveguide and two output ports are microstrip lines. The measured results of the power divider show above 12-dB minimum isolation over 13–16 GHz, with an input return loss of better than 15 dB. The return loss of the output ports is better than 10 dB, with an insertion loss of lower than 0.35 dB. A maximum amplitude imbalance of about 0.15 dB is observed within 13–16 GHz, with a phase imbalance of better than 2.5°. The proposed power divider in this letter is compact and good integration with the monolithic microwave integrated circuit (MMIC) devices.

An S-Band Microstrip Patch Antenna Design and Simulation for Wireless Communication Systems

Abstract: In this paper, a 3.5 GHz microstrip patch antenna for the future of wireless communication is designed and studied. As a substrate, Rogers RT/Duroid5880 is utilized. This material has a thickness of 0.077mm and a dielectric loss of 2.2. The proposed antenna layout is simulated using the CST studio suite of software programs. This research aimed to achieve a lower return loss, higher gain, lower VSWR, directivity, and improved efficiency. The simulation revealed that the return loss, gain, VSWR, and directivity were correspondingly -13.772 dB, 7.55 dB, 1.5152, and 8.43dBi. The efficiency was 89.56%. This antenna has been developed and assessed for use in various wireless communication applications with a 3.5 GHz operating frequency, which is used as a reference antenna in communication satellites, weather radar, surface ship radar, wireless LAN-802.11b and 802.11g, multimedia applications in mobile TV and satellite radio, optical communications at 1460 to 1530 nm wavelength, and is utilized for other wireless fidelity applications.

Analysis and design of ultra-wideband PRGW hybrid coupler using PEC/PMC waveguide model

Abstract: Abstract In this paper, a new method to facilitate the design of Printed Ridge Gap Waveguide (PRGW) structures is introduced. One of the main difficulties in designing such structures is related to their simulation process which is really time and energy-consuming. Therefore, a suitable boundary condition is considered to bring about the primary structure without involving the bed of nails or mushroom unit cells. Using this technique, a wideband PRGW 3 dB hybrid double-box coupler is designed to serve in mm-wave frequencies at a center frequency of 30 GHz, which can be deployed for the next generation of mobile communication. The designed coupler provides a wide matching and isolation bandwidth with low output amplitude imbalance, which is unique in comparison with current couplers. The prototype of the proposed coupler is fabricated and measured where the simulation and measurement results show a good agreement indicating the strength of the proposed method in PRGW structure design as well. The measured results show the couplers achieve better than 10-dB return loss and isolation over the frequency range from 25 to 40 GHz (46% BW) with the power-split unbalance and phase error within ± 1 dB and ± 5°, respectively. In addition, square mushrooms are chosen here to satisfy the high impedance surface. Not only do they bring about larger stop bandwidth, but also their configuration facilitates the arrangement of them around the coupler. The proposed design has superb characteristics such as low profile, low loss, and easy integration with microwave circuits and systems that can be suitable for designing mm-wave beamforming networks.

A Terahertz Band-Pass Filter Based on Coplanar-Waveguide and Spoof Surface Plasmon Polaritons

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.

Channel Characterization of Magnetic Human Body Communication

Abstract: The objective of this paper is to model and experimentally validate the path loss benefits of magnetic human body communication (mHBC) using small form-factor-accurate coils operating under realistic conditions.A radiating near-field coupling model and numerical simulations are presented to show that the magnetic-dominant near-field coupling between resonant coils offers low path loss across the body and exhibits extra robustness to antenna misalignment compared to far-field RF schemes. To overcome the pitfalls in conventional vector-network-analyzer-based measurement configurations, we propose a standardized setup applied to broadband channel loss measurement with portable instruments. Two types of PCB coils for mHBC communication, designed for large devices such as smartphones and small devices such as earbuds, respectively, are built and measured.The mHBC link for the ear-to-ear non-line-of-sight (NLOS) path measures up to -23.1 dB and -31.2 dB with large and small coils, respectively, which is 50 dB more efficient than the conventional Bluetooth channels utilizing antennas of similar sizes. Ear-to-pocket and pocket-to-pocket channels also show at least 16 dB higher transmission than the Bluetooth channel.In terms of path loss, the mHBC approach offers compelling performance for short-range applications over the body region. For coils with dimensions of several centimeters, working between 100 MHz and 200 MHz minimizes the channel loss while keeping the bandwidth above 1 MHz.The extremely high efficiency of the proposed mHBC channel provides a solution to the energy problem for miniaturized wearables, potentially leading to new wearable device designs.

Wideband Flat Negative Group Delay Circuit With Improved Signal Attenuation

Abstract: A novel wideband flat negative group delay (NGD) circuit with improved signal attenuation is proposed. The proposed negative group delay circuit (NGDC) is composed of three transmission lines and two parallel branches, which are consisted of two series transmission lines with a resistor linking to a T-type stub. The complete closed-form design equations are presented. For verification, an NGDC is designed, fabricated, and measured at the center frequency of 2.14 GHz. From the measured results, NGD time of −1.11 ns at the center frequency is obtained with an insertion loss of 9.75 dB and return loss of 22.3 dB. The flat-NGD bandwidth reaches 6.1% from 2.072 to 2.202 GHz with ±11.5% group-delay fluctuation.

A Harmonic-Free Wilkinson Power Divider Using Lowpass Resonators

Abstract: This paper presents a Wilkinson power divider (WPD) capable of suppressing unwanted bands up to 16th harmonic with high isolation. In this WPD, a lowpass filter composed of a main resonator and three bended stubs are used to guarantee a wide stopband. The presented WPD illustrates suitable performance at 0.85 GHz for GSM applications. Isolation between of output ports, input return loss and insertion loss are better than 24 dB, 20 dB and 3.4 dB, respectively.

Novel measurement technique to detect breast tumor based on the smallest form factor of UWB patch antenna

Abstract: Abstract A small ultra-wideband (UWB) patch antenna for microwave breast imaging (MWI) applications is shown off in this paper. However, to improve the antenna performance relating to the bandwidth (BW), the radiating element of the suggested antenna is modified by adding slits in the patch as well as the ground plane. The proposed prototype has a relatively small size of 20 × 19 × 1.6 mm 3 and it accomplishes a return loss below −10 dB ( S 11< −10 dB) at an overall BW of 7 GHz (4–11 GHz) with more than 3 dBi realized gain. The antenna is designed and simulated by using a finite integration technique-based simulator. In this way, the characteristics of the fabricated antenna are measured to examine the antenna performance. Indeed, the fidelity factor of face-to-face (FtF) and side-by-side (SbS) scenarios are also noticed for the same frequency range. In the final analysis, a simulation model of the antennas, that operate as a transceiver, and a breast phantom model with tumor sample is proposed for detecting cancerous tumor cells within the breast. Hence, the proposed approach is suitable for UWB based MWI applications in tumor cell detection.

Archimedean Spiral Slotted Leaky-Wave Antenna

Abstract: In this work, a novel leaky-wave antenna (LWA) with Archimedean spiral slots is proposed for realizing high radiation efficiency and stable gain performance in both frequency-controlled and fixed-frequency beam-scanning applications. The structural feature of the proposed Archimedean spiral slot privileges LWA with properties of easy impedance matching and high leakage rate, because it avoids the strong reflection from large-size slots that commonly used in LWA design for high leakage rate. The bandwidths of the final designed Ka-band LWA defined by radiation efficiency larger than 90% and 80% are 13% and 25%, respectively, while the bandwidth defined by return loss less than −10 dB is 29%. And the gain fluctuations between different scanned beams are less than 2.4 dBi in the whole broadband. The LWA is further applied in designing a new-type antenna with double-layer substrate-integrated waveguide (SIW) structures, which has four feeding ports at the ends and a coupling plane in the middle interface and can realize the fixed-frequency beam switching between directions of −46°, −36°, 34°, and 45° at 28 GHz through changing the excitation port. The proposed LWAs are potential candidates for applying in future millimeter wave communication systems where multifunction integrated and multifrequency adaptive antennas are required.

A Novel Capacitive Microwave Power Sensor Based on Double MEMS Cantilever Beams

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.

An FR4-Based Self-Packaged Full Ka-Band Low-Loss 1:4 Power Divider Using SISL to Air-Filled SIW T-Junction

Abstract: An FR4-based full Ka-band 1:4 passive power divider using substrate integrated suspended line (SISL) technology is presented in this letter and it achieves a relatively low insertion loss. A SISL to air-filled substrate integrated waveguide (SIW) T-junction with an iris structure is proposed as the first stage of the divider to obtain wideband matching, and a bandwidth of 61.7% is achieved. The power-handling capability of the power divider is studied. A back-to-back 1:4 power divider was fabricated, and the measured results agree well with the simulated ones. From 25.2 to 40 GHz, i.e., a 45.5% fractional bandwidth, the measured return loss is better than 15 dB, and the measured insertion loss is less than 1.2 dB. Moreover, the isolation performance is improved from 2.5 to 15 dB by adding three ports connected with the load resistor.

Design of a Modified Compact Coupler with Unwanted Harmonics Suppression for L-Band Applications

Abstract: This paper presents the design, analysis, and fabrication of a new miniaturized microstrip branch line coupler (BLC) with high harmonics suppression. The T-shaped resonators, open stubs cross-shaped resonators and radial stubs are used in the proposed coupler design. The designed BLC operates at 1 GHz frequency, which can suppress up to 5th spurious harmonics with a 20 dB level of attenuation. High miniaturization of about 86% is obtained for the proposed BLC, which is corresponding to the normalized size of 0.009 λg2. The measured values of isolation and return loss are obtained 28 dB and 29 dB, respectively, while the measured insertion loss of better than 0.2 dB is achieved at the operating frequency. Additionally, the operating bandwidth of the designed coupler ranges from 0.905 GHz up to 1.105 GHz, which shows a 200 MHz operating bandwidth or a fractional bandwidth (FBW) of 20%. The presented BLC is fabricated and measured, where the measurements confirm the simulated results. The designed coupler shows desirable performance compared to the recent designed couplers.

Insertion Loss and Phase Compensation Using a Circular Slot Via-Hole in a Compact 5G Millimeter Wave (mmWave) Butler Matrix at 28 GHz

Abstract: Fifth generation (5G) technology aims to provide high peak data rates, increased bandwidth, and supports a 1 millisecond roundtrip latency at millimeter wave (mmWave). However, higher frequency bands in mmWave comes with challenges including poor propagation characteristics and lossy structure. The beamforming Butler matrix (BM) is an alternative design intended to overcome these limitations by controlling the phase and amplitude of the signal, which reduces the path loss and penetration losses. At the mmWave, the wavelength becomes smaller, and the BM planar structure is intricate and faces issues of insertion losses and size due to the complexity. To address these issues, a dual-layer substrate is connected through the via, and the hybrids are arranged side by side. The dual-layer structure circumvents the crossover elements, while the strip line, hybrids, and via-hole are carefully designed on each BM element. The internal design of BM features a compact size and low-profile structure, with dimensions of 23.26 mm × 28.92 mm (2.17 λ0 × 2.69 λ0), which is ideally suited for the 5G mmWave communication system. The designed BM measured results show return losses, Sii and Sjj, of less than −10 dB, transmission amplitude of −8 ± 2 dB, and an acceptable range of output phase at 28 GHz.

A Simple Method to Design a UWB Filter with a Notched Band Using Short-Circuit Step Impedance Stubs

Abstract: This article presents a simple method to design an ultra-wideband (UWB) bandpass filter (BPF) with a notched band. The structure of the filter is simple and is composed of a single half-wavelength resonator loaded with three sets of short-circuit step impedance stubs. An equivalent circuit model is presented to analyze the resonance characteristics. Compared with the traditional quarter-wavelength uniform impedance stub, the novelty of the short-circuit step impedance stub introduces two design parameters: the impedance ratio (K) and the electrical length ratio (α). Therefore, by adjusting these design parameters, the frequencies of the first two notched bands can be tuned widely, so a wide frequency band with a notched band can easily be achieved. With a K of 0.36 and an α of 0.6, the designed filter achieved an ultra-wideband bandpass response with a notched band. The UWB response had a passband range of 2.5 GHz–10.5 GHz and a notched band around 5.1 GHz with an attenuation of about 45 dB. The insertion loss in the entire passband was less than 1.26 dB, and the return loss was larger than 10 dB on average. The maximum group delay variation in the two passbands was less than 0.3 nS. The measurement results showed good agreement with the simulation results.

<i>X</i>-Band Ferrite Microstrip Limiter Based on Improved Nonlinear Loss Model for High-Power Microwave Application

Abstract: An improved ferrite nonlinear (NL) loss theory is developed for polycrystal ferrite microstrip limiters upon the high-power microwave (HPM) environment. The NL critical threshold equation and equivalent loss model are derived from the field coupling mechanism between spin waves and microwave pulse. Thus, the equivalent NL loss behavior with the microwave waveform parameters (pulse duration and power) is implanted in the ferrite limiter model to perform the numerical simulation through the commercial electromagnetic tool. The measured limiting data at pulse duration with 60, 80, 100, and 200 ns are in good agreement with the equivalent simulation results.

A Compact Wide Stopband Band Pass SIW Filter For K-Band Applications

Abstract: Direct coupled filters have narrow stopband due to higher order modes passband. A compact dual layer band pass filter is proposed with wide stop band. The proposed filter provides the return loss of 16.87db and insertion loss of 2.5dB at the passband frequency 20.9 GHz. The filter size is half of the conventional direct coupled filters. The stop band covers up to 40 GHz with insertion loss below 35dB. The filter has no slot which makes it immune to the EMI/EMC problems.

Cryogenic Wideband Quadrature Hybrid Couplers Implemented in a Low Temperature Superconductor Multilayer Process

Abstract: This paper presents the design, fabrication and testing of two cryogenic 90° hybrid couplers operating at Ka and Ku bands. The hybrid couplers use a CPW based tandem coupled line architecture and are fabricated using a MIT Lincoln Lab multilayer process for superconducting circuits. The first quadrature hybrid demonstrates a wideband coupling performance from 26 GHz to 44 GHz, with measured return loss and isolation better than 24 dB, and insertion loss less than 0.5 dB. The second tandem coupler offers an excellent coupling performance from 8 GHz to 18 GHz. The on-chip device dimensions for the two hybrid couplers are 0.92 mm × 0.16mm and 2.43 mm × 0.16mm, respectively. For further miniaturization, an alternative compact hybrid coupler design for operation at Ku band is proposed having a footprint of only 0.41 mm × 0.35mm, a 64% reduction in device area when compared to the first Ku band design.

Low‐loss X‐band waveguide bandpass filter based on rectangular resonators

Abstract: This paper presents a procedure for designing and synthesizing a 5th‐order waveguide bandpass filter based on rectangular resonators in X‐band frequency. The designed bandpass filter is implemented in waveguide technology with multiple rectangular cavity resonators. Computerized numerical control (CNC) micro‐machined metallic is used in the waveguide filter structure with an accuracy of 0.2 mm. silver plating has been performed inside the X‐band bandpass filter, which has improved the quality of the response. This low‐loss and high‐power X‐band wideband waveguide filter with center frequency at 9.45 GHz, the bandwidth of 0.9 GHz, the return loss of 18 dB, and the insertion loss of 0.08 dB has been realized.

Wideband Highly-Selective Bandpass Filtering Branch-Line Coupler

Abstract: This paper presents a novel design of a wideband highly-selective bandpass filtering branch-line coupler (FBLC). By integrating a coupled microstrip line, and an open-ended stub at each port of a single-section BLC, bandpass filtering characteristics with excellent selectivity and broad operating bandwidth have been achieved. The proposed circuit has been verified through EM simulations and physical measurements of the fabricated prototype. Experimental results demonstrate over 71-percent fractional bandwidth (2.25 GHz to 4.74 GHz) with a power imbalance lower than 0.5 dB. At the same time, the measured return loss and isolation are better than 15dB with the phase imbalance of 5 ± 5°. This level of performance, especially in terms of bandwidth and selectivity, has not been reported in the literature thus far.