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Showing papers on "Return loss published in 2013"


Patent
08 May 2013
TL;DR: In this paper, a mobile device with at least two antennas coupled to fractional amplifiers, with returned power detectors, is used to measure a return power level, if output power is greater than a specific absorption rate level, then implement mobile transmit diversity (MTD) combined with reflection-based beamforming to create an adaptive beam pattern.
Abstract: A system may include a modifiable mobile device having at least two antennas coupled to fractional amplifiers, with returned power detectors. A beamformer unit provides adaptive beam shaping pattern, and a baseband processor provides beam pattern requirements, wherein the beamformer unit modifies the beam pattern requirements with return loss sampling information to shape the adaptive beam pattern so that a transmitted beam pattern minimizes transmitted power reflected back to the mobile device. A method may include regularly measuring a return power level, if output power is greater than a specific absorption rate level, comparing the return power level to a first threshold, else implementing mobile transmit diversity (MTD), and repeating. If the return power level is greater than the first threshold, implementing a MTD combined with reflection-based beamforming that modifies beam pattern requirements of the mobile device with return loss sampling information to create an adaptive beam pattern.

238 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed the concept and design of terahertz phase shifters for phased antenna arrays based on integrally-gated graphene parallel-plate waveguides (GPPWGs).
Abstract: We propose the concept and design of terahertz (THz) phase shifters for phased antenna arrays based on integrally-gated graphene parallel-plate waveguides (GPPWGs). We show that an active transmission-line may be realized by combining GPPWGs with double-gate electrodes, in which the applied gate voltage can control the guiding properties of the gated sections. This may enable the realization of THz electronic switches and tunable loaded-lines for sub mm-wave antenna systems. Based on these active components, we theoretically and numerically demonstrate several digital and analog phase shifter designs for THz frequencies, with a wide range of phase shifts and small return loss, insertion loss and phase error. The proposed graphene-based phase shifters show significant advantages over other available technology in this frequency range, as they combine the low-loss and compact-size features of GPPWGs with electrically-programmable phase tuning. We envision that these electronic phase shifters may pave the way to viable phased-arrays and beamforming networks for THz communications systems, as well as for high-speed, low-RC-delay, inter/intra-chip communications.

184 citations


01 Jan 2013
TL;DR: In this article, a simple dielectric Resonator Antenna (DRA) for X band frequency operation is proposed, which gives dual band operation in X band and resonates at frequency 8.6 GHz and 10.3 GHz respectively.
Abstract: A simple Dielectric Resonator Antenna (DRA) for X band frequency operation is proposed in this paper. X band is a microwave band lies between frequency range 8 to 12 GHz. In proposed DRA reflector plane is used beneath the microstrip feed line with a small air gap, introduced between feed substrate and reflector plane to reduce the back lobe. Slot coupling is used to excite this DRA. Proposed DRA design gives dual band operation in X band and resonates at frequency 8.6 GHz and 10.3 GHz. Antenna design offers minimum return loss of -20.3 db and -24.5 db at 8.6 GHz and 10.3 GHz respectively. It also offers high front to back ratio (FBR) of 12.35db and 9.83 db at 8.65 GHz and 10.3 GHz respectively. Return loss impedance bandwidth of 390 MHz (4.5%) for Band I and 730MHz (7.3%) for band II is obtained. Simple DRA design with high FBR is proposed here for X band application that shows a total bandwidth of 11.8%. DRA is analysed using Ansoft HFSS based on finite element method. Radiation characteristics of this DRA are observed at resonating frequencies. This DRA is useful at microwave X band application such as satellite communication.

130 citations


Journal ArticleDOI
TL;DR: The proposed antenna could be a suitable candidate for advanced and smart radio applications such as cognitive radio (CR) as it can enhance the radio front-end flexibility and performance by adding the benefits of pattern diversity, specifically in multipath environments.
Abstract: A novel pattern-reconfigurable compact planar ultra-wideband monopole antenna is presented. By the incorporation of four p-i-n diode switches and two parasitic elements, the antenna's radiation patterns can be shaped to concentrate energy in specific directions while minimising the gain in other unwanted directions without significantly affecting the impedance bandwidth of the antenna. A fully functional prototype has been developed and tested. The measured results of the return loss, radiation patterns, and realised gain verify the effectiveness of the proposed antenna configuration. The antenna switches its radiation patterns between an omni-directional mode and two directional modes with opposite directions in the operating range from 3 to 6 GHz. The proposed antenna could be a suitable candidate for advanced and smart radio applications such as cognitive radio (CR) as it can enhance the radio front-end flexibility and performance by adding the benefits of pattern diversity, specifically in multipath environments.

95 citations


Journal ArticleDOI
TL;DR: A novel ultrawideband (UWB) ring-cavity multiple-way parallel power divider is presented and the approximated equivalent-circuit model of the power-dividing unit is presented to analyze its structural parameters and electrical performance.
Abstract: A novel ultrawideband (UWB) ring-cavity multiple-way parallel power divider is presented in this paper. The approximated equivalent-circuit model of the power-dividing unit is presented to analyze its structural parameters and electrical performance. The overall circuit model of the proposed power divider is also given. To verify its potential to accommodate large numbers of power-dividing ports, a UWB 32-way ring-cavity power divider is developed with reasonable agreement between the simulated and measured results. The measured return loss is greater than 10 dB over the entire UWB and also greater than 15 dB from 4.2 to 9.2 GHz. The average insertion loss, amplitude imbalance, phase imbalance, and group delay are around 15.4 dB (including the 15-dB power-dividing insertion loss), ±0.7 dB, ±5°, and 0.85 ns, respectively, across the UWB. In addition, the isolations between the output ports are greater than 10 dB over the UWB except for those between the adjacent output ports.

87 citations


Journal ArticleDOI
TL;DR: In this paper, a simple and low-loss microstrip-to-ridge gap waveguide transition with a very compact geometry is described, in which the height of the air gap in the ridge gap is kept almost equal to the thickness of the substrate of the microstrip line.
Abstract: This letter describes a simple and low-loss microstrip-to-ridge gap waveguide transition with a very compact geometry. The transition transforms the electromagnetic (EM) fields from the microstrip mode to the air-filled ridge gap waveguide mode. This is achievable if the height of the air gap in the ridge gap waveguide is kept almost equal to the thickness of the substrate of the microstrip line. The transition has a pressure contact between the ridge and the microstrip line, so it works without soldering. This is advantageous in systems that require mechanically separable split-blocks or modules and need a lot of transitions. Experimental results of the manufactured back-to-back transition show an insertion loss of 0.32 dB and a return loss of 14.15 dB over 55% relative bandwidth in Ka-band.

80 citations


Journal ArticleDOI
23 Jan 2013
TL;DR: In this article, a new type of microstrip dual-mode dual-band bandpass filter (BPF) using a single quadruple-mode resonator (QMR) is proposed.
Abstract: A new type of microstrip dual-mode dual-band bandpass filter (BPF) using a single quadruple-mode resonator (QMR) is proposed in this paper. The classical even-/odd-mode method is applied to analyze the characteristics of the proposed resonator, which shows that it has two pairs of symmetrical resonant modes. Owing to the inherent characteristic of a dual-mode resonator and source-load coupling, four transmission zeros can be produced and these four resonant modes can be divided in two groups, resulting in a dual-band BPF with two resonant modes in each passband. As examples, two dual-mode dual-band BPFs, Filter A with central frequencies (CFs) at 1.99/5.58 GHz and -3-dB fractional bandwidth (FBW) of 62.3%/19.7%, while Filter B with CFs at 1.64/5.26 GHz and -3-dB FBW of 32.9%/7.6%, are designed and fabricated. An aperture-backed compensation technique is employed in such two filters to enhance the coupling strength between the feeding lines and QMR. Furthermore, a meander coupled-line section is employed in the Filter A design, while a defected microstrip structure is introduced in Filter B design, so as to increase much more design freedoms for tuning filter performance. The fabricated two filters exhibit simple design procedures, low insertion losses, good return losses, sharp shirts, and compact sizes. Moreover, two BPFs do not need external input/output impedance transformation feeding lines.

73 citations


Journal ArticleDOI
TL;DR: In this article, a symmetrical coupled-line circuit structure without patterned ground plane is proposed to design tight-coupling high-directivity couplers, which would be found in numerous applications in a microstrip RF front end.
Abstract: A novel symmetrical coupled-line circuit structure without patterned ground plane is proposed to design tight-coupling high-directivity couplers, which would be found in numerous applications in a microstrip RF front end because of its simple structure and inherent excellent compatibility. Based on a traditional even- and odd-mode technique, closed-form mathematical equations for both circuit electrical parameters and scattering parameters are obtained. Due to the use of two coupled-line sections placed in the vertical direction, the directivity of this novel coupler without any other compensation techniques can be enhanced while maintaining tight-coupling performance of almost 3 dB. For demonstrative purposes, three typical full-wave simulation examples with realized physical dimensions in microstrip technology are presented, indicating high directivity and tight coupling coefficient. Finally, a practical microstrip coupled-line coupler is designed and fabricated to operate at approximately 2 GHz. The measured results show good return loss, quadrature phase characteristics, high directivity, and strong coupling performances.

71 citations


Journal ArticleDOI
TL;DR: This unique soft antenna is a good candidate for receiving digital television and wireless communications in a smart clothing environment and interposing a layer of felt fabric between the antenna and the phantom typically improved efficiency by over 50%.
Abstract: A dual band textile antenna designed for Digital Television (DTV) and many wireless standards including GSM 900, WLAN 2.45/5.8 GHz, Wimax 3.5 GHz, Hyperlan 5.2 GHz and UMTS-LTE-advanced is described. The impact of the body on antenna performance is assessed for return loss, radiation patterns and antenna efficiency in a wide frequency range. Full three dimensional radiation patterns were measured with the antenna backed by a phantom in order to simulate a human body. While the return loss was found to be only marginally affected when the antenna was mounted at various positions on the human body, the measured efficiency was observed to decrease by up to 90% when the antenna was positioned flush to the phantom. The return loss response was little affected when the antenna was worn on the back and further covered with a number of garments including a thick woolen jumper and a ski jacket. Although antenna efficiency was substantially affected by the presence of the body, interposing a layer of felt fabric between the antenna and the phantom typically improved efficiency by over 50%. This unique soft antenna is a good candidate for receiving digital television and wireless communications in a smart clothing environment.

71 citations


Journal ArticleDOI
TL;DR: In this article, the fabrication of void-free copper-filled through-glass-vias (TGVs) and their application to the wafer-level radio frequency microelectromechanical systems (RF MEMS) packaging scheme is presented.
Abstract: We present a novel method for the fabrication of void-free copper-filled through-glass-vias (TGVs), and their application to the wafer-level radio frequency microelectromechanical systems (RF MEMS) packaging scheme. By using the glass reflow process with a patterned silicon mold, a vertical TGV with smooth sidewall and fine pitch could be achieved. Bottom-up void-free filling of the TGV is successfully demonstrated through the seedless copper electroplating process. In addition, the proposed process allows wafer-level packaging with glass cap encapsulation using the anodic bonding process, since the reflowed glass interposer is only formed in the device area surrounded with silicon substrate. A simple coplanar waveguide (CPW) line was employed as the packaged device to evaluate the electrical characteristics and thermo-mechanical reliability of the proposed packaging structure. The fabricated packaging structure showed a low insertion loss of 0.116 dB and a high return loss of 35.537 dB at 20 GHz, which were measured through the whole electrical path, including the CPW line, TGVs and contact pads. An insertion loss lower than 0.1 dB and a return loss higher than 30 dB could be achieved at frequencies of up to 15 GHz, and the resistance of the single copper via was measured to be 36 mΩ. Furthermore, the thermo-mechanical reliability of the proposed packaging structure was also verified through thermal shock and pressure cooker test.

69 citations


Journal ArticleDOI
TL;DR: In this article, a dual-polarized double E-shaped patch antenna with high isolation for pico base station applications is presented, which employs a stacked configuration composed of two layers of substrate.
Abstract: A compact dual-polarized double E-shaped patch antenna with high isolation for pico base station applications is presented in this communication The proposed antenna employs a stacked configuration composed of two layers of substrate Two modified E-shaped patches are printed orthogonally on both sides of the upper substrate Two probes are used to excite the E-shaped patches, and each probe is connected to one patch separately A circular patch is printed on the lower substrate to broaden the impedance bandwidth Both simulated and measured results show that the proposed antenna has a port isolation higher than 30 dB over the frequency band of 25 GHz - 27 GHz, while the return loss is less than - 15 dB within the band Moreover, stable radiation pattern with a peak gain of 68 dBi - 74 dBi is obtained within the band

Journal ArticleDOI
TL;DR: In this article, a W-band TE01 mode gyrotron traveling-wave tube (gyro-TWT) amplifier is designed, and it features high gain and broadband capabilities.
Abstract: A pulse prototype of a W-band TE01 mode gyrotron traveling-wave tube (gyro-TWT) amplifier is designed, and it features high gain and broadband capabilities. The TE01 mode input coupler is constructed by mounting a sapphire pill-box window onto a Y-type mode converter. The high power output window will employ a triple-sapphire-disc configuration to achieve return loss lower than -30 dB over a bandwidth of 8 GHz. To suppress the spurious oscillations and realize high-average power potential, a new lossy ceramic material with weak electric conductivity is loaded in the TE01 mode cylindrical interaction waveguide. The loss-free output taper is carefully optimized to suppress oscillations and maintain broadband amplification. Employing a magnetic injection gun of beam voltage 70 kV, beam current 3 A, pitch factor 1.5, and axial-velocity spread 5%, theoretical investigation predicts that the gyro-TWT amplifier is of excellent performance, which includes being driven to saturation with input power Pin <; 0.4 W, highest efficiency of 32.4%, and the bandwidth of 4.2 GHz with output power exceeding 50 kW.

Journal ArticleDOI
TL;DR: In this article, an efficient, compact, and high-isolation waveguide duplexer operating at 225 GHz is presented. But the design presented in this paper uses a ferrite-free duplexing concept based on transmitting and receiving in orthogonal circular polarizations.
Abstract: In this paper, we present the modeling and experimental validation of an efficient, compact, and high-isolation waveguide duplexer operating at 225 GHz. While duplexers based on ferrite circulators are key components of many monostatic radar systems, at W-band frequencies and above the performance of waveguide circulators rapidly deteriorates. The design presented here uses a ferrite-free duplexing concept based on transmitting and receiving in orthogonal circular polarizations. The circular polarization is efficiently generated in waveguide using a septum orthomode transducer polarizer, leading to a compact device with a single horn antenna. The complete duplexer is designed using efficient numerical algorithms, resulting in a fabricated device with a measured 10% fractional bandwidth, a return loss better than 20 dB, isolation of 30 dB, and insertion loss below 1 dB.

Journal ArticleDOI
TL;DR: In this paper, a concept of simultaneous electric and magnetic 2D tuning is presented, demonstrated, and applied for the first time through the theoretical and experimental studies of parameter-agile substrated integrated waveguide (SIW) devices.
Abstract: A concept of simultaneous electric (E) and magnetic ( H) 2-D tuning is presented, demonstrated, and applied for the first time through the theoretical and experimental studies of parameter-agile substrated integrated waveguide (SIW) devices. First of all, a two-dimensionally tuned SIW cavity is introduced as a building block. Considering only electric tuning with varactor diodes, no more than 1.3% of total tuning range is accomplished, while for simultaneous electric and magnetic tuning, it is extended to 7.9% with an unloaded Q factor of better than 130. Using 0.05-0.1-pF surface mount capacitors, a total tuning range of as much as 20% is experimentally achieved at 12 GHz. Another characteristic of significant interest is that the proposed 2-D tuning not only allows changing frequency, but also simultaneously optimizing other key parameters such as the return loss or unloaded Q factor. Second, the dual-tuned SIW cavity resonator is further accommodated to demonstrate parameter agile two-dimensionally tuned bandpass filter at 12 GHz. The proposed concept of 2-D tuning theoretically and experimentally demonstrates a simultaneous frequency and bandwidth tuning of bandpass filter. This filter can perform both frequency-tunable constant bandwidth, and constant-frequency variable-bandwidth operations. Third, a cavity backed slot antenna using the proposed dual tuning is demonstrated. The tuning not only achieves a higher frequency range, but the antenna return loss is optimized to improve the overall efficiency.

Journal ArticleDOI
TL;DR: The parametric study of the proposed Coplanar Waveguide fed double L slot antenna array shows that the features of the small antenna structure, good radiation characteristics are promising for multi input multi output operation.

Journal ArticleDOI
TL;DR: In this article, a CMOS true-time delay (TTD) circuit operating from 15 to 40 GHz is presented for integrated UWB multi-antenna systems, which employs a distributed active switching structure in which eight cascode switches are distributed along transmission lines, leading to 3-bit variations of the group delay.
Abstract: A CMOS true-time delay (TTD) circuit operating from 15 to 40 GHz is presented for integrated UWB multi-antenna systems. The TTD circuit employs a distributed active switching structure in which eight cascode switches are distributed along transmission lines, leading to 3-bit variations of the group delay. The size of the switches and the characteristic impedance of the transmission lines are carefully scaled so as to minimize loss variation among the different delay states, while maintaining flat delay performance over a wide bandwidth. The circuit is implemented in a bulk 0.13-μm CMOS technology and exhibits a total variable group delay of 40 ps with an average resolution of 5 ps from 15 to 40 GHz. The insertion loss was 14 dB with a maximum RMS variation of 1.6 dB, while the input and output return loss was better than 10 dB over the operating bandwidth.

Journal ArticleDOI
TL;DR: In this article, two canonical filter topologies based on E- and H-plane are implemented for the DRIE silicon micromachining process for the fabrication of the filters.
Abstract: In this letter, several bandpass filters operating in the WR-1.5 band (500 to 750 GHz) are presented. The deep reactive ion etching (DRIE) silicon micromachining process is used for the fabrication of the filters. Two canonical filter topologies based on E- and H-plane are implemented. The work presented here has two specific objectives: a) to get important fabrication process parameters, such as tolerances, vertical angles, surface roughness, and repeatability and b) to validate the proper working of the waveguide filters in the terahertz band. These filters do not have any tuning element. Experimental results show better than 10 dB return loss and approximately 1 and 2.5 dB insertion loss (for 6% fractional bandwidth) for the E- and H-plane topology, respectively. The obtained results are in agreement with fabrication tolerances of 2 μm and vertical angles deviations up to 3°.

Journal ArticleDOI
TL;DR: In this article, a superconducting ultra-wideband (UWB) bandpass filter (BPF) with sharp rejection skirts and miniaturized size using multiple-mode resonator (MMR) is presented.
Abstract: This letter presents a superconducting ultra-wideband (UWB) bandpass filter (BPF) with sharp rejection skirts and miniaturized size using multiple-mode resonator (MMR). The MMR is formed by loading a stepped-impedance open-end stub in shunt to a modified stepped-impedance resonator (SIR). The modified SIR generates three resonant modes within the 3.1-10.6 GHz UWB band, whereas the stepped-impedance open-end stub creates two transmission zeros and two additional resonant modes improving the bandedge steepness. Interdigital coupled-lines are used for the external couplings to enhance the coupling strength. A superconducting UWB BPF is realized with a compact size of 20 mm × 11 mm. The measured results without any tuning show good performance. The insertion loss at the center frequency is 0.58 dB, the return loss is greater than 10.6 dB, and the group delay variation is less than 1.76 ns. Furthermore, the experimental results of the filter are in good agreement with the simulated ones.

Journal ArticleDOI
TL;DR: In this article, a rat-race coupler design with tunable power dividing ratio is presented, for the first time, which is accomplished by the use of two tuning diodes and a single control voltage.
Abstract: This paper presents, for the first time, a novel rat-race coupler design with tunable power dividing ratio. Wide tuning ratio is accomplished by the use of two tuning diodes and a single control voltage. Ideal port isolation and return loss characteristics, evaluated at the center frequency of operation, are proven for all dividing ratios. The structure is simple to construct and involves 50-ohm lines only. For verification, the simulated and measured results of a 1-GHz rat-race coupler implemented on microstrip are shown.

Journal ArticleDOI
TL;DR: In this paper, a rectenna based on a microstrip dipole antenna and a microwave rectifler with high conversion efficiency was designed at 2.45GHz, achieving a gain of 5.2dBi, a return loss greater than 10dB, and a bandwidth of 20%.
Abstract: The microwave power transmission is an approach for wireless power transmission. As an important component of a microwave wireless power transmission systems, microwave rectennas are widely studied. A rectenna based on a microstrip dipole antenna and a microwave rectifler with high conversion e-ciency were designed at 2.45GHz. The dipole antenna achieved a gain of 5.2dBi, a return loss greater than 10dB, and a bandwidth of 20%. The microwave to DC (MW-DC) conversion e-ciency of the rectifler was measured as 83% with 20dBm input power and 600› load. There are 72 rectennas to form an array with an area of 50cm by 50cm. The measured results show that the arrangement of the rectenna connection is an efiective way to improve the total conversion e-ciency, when the microwave power distribution is not uniform on rectenna array. The experimental results show that the highest microwave power transmission e-ciency reaches 67.6%.

Patent
18 Oct 2013
TL;DR: In this paper, the authors proposed to sub-divid the crosstalk stages into a plurality of time-delayed discrete elements, and achieved improved return loss and insertion loss for very high frequency signals.
Abstract: Communications connectors include a plurality of “discrete” elements to implement the capacitive and/or inductive components of offending and/or compensatory crosstalk stages. By sub-dividing the crosstalk stages into a plurality of time-delayed discrete elements improved return loss and insertion loss may be achieved for very high frequency signals, without having a substantial impact on the crosstalk performance of the connector.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a miniature branch-line coupler and Butler matrix designs for 2.5 GHz applications using the glass-based thin-film integrated passive device (TF-IPD) technology.
Abstract: In this paper, miniature branch-line coupler and Butler matrix designs for 2.5-GHz applications are proposed using the glass-based thin-film integrated passive device (TF-IPD) technology. The size reduction is achieved by replacing the quarter-wavelength transmission lines in a conventional branch-line coupler with the bridged-T coil. In this way, the circuit size can be largely reduced without sacrificing the operation bandwidth. The proposed miniature branch-line coupler is then applied to the design of a 4 × 4 Butler matrix centered at 2.5 GHz using the glass-based TF-IPD technology. The measured results show a bandwidth of 2.4-2.6 GHz for better than 13-dB return loss with a maximal dissipation of 4 dB, amplitude imbalance within 1.1 dB, and phase imbalance less than 13°. Notably, the proposed Butler matrix occupies a chip area of 3.13 mm × 3.3 mm, which is only about 0.026 λ0 × 0.027 λ0 at 2.5 GHz.

Journal ArticleDOI
TL;DR: In this article, a X-band wideband bandpass fllter based on a novel substrate integrated waveguide-to-defected ground structure (SIW-DGS) cell is presented.
Abstract: In this paper, a X-band wideband bandpass fllter based on a novel substrate integrated waveguide-to-defected ground structure (SIW-DGS) cell is presented. In the cell, the DGS is etched on the top plane of the SIW with high accuracy, so that the performance of the fllter can be kept as good as possible. Finally, the fllter, consisting of three cascaded cells, is designed and measured to meet compact size, low insertion loss, good return loss as well as smooth group delay. There is good agreement between the measurement and simulation results.

Journal ArticleDOI
TL;DR: In this article, a compact wideband circularly polarized (CP) patch antenna utilizing a quad-feed network (QFN) and quadruple semi-fan-annulus (QSFA) patches is proposed.
Abstract: A compact wideband circularly polarized (CP) patch antenna utilizing a quad-feed network (QFN) and quadruple semi-fan-annulus (QSFA) patches is proposed. For using a coupled-line dual-band power divider (PD) and improved phase shifter (PS) with stepped-impedance-open-stub (SIOS), the QFN has a compact size and exhibits the electromagnetic (EM) simulated bandwidth over 96% for the power distribution -6.5±0.5 dB, return loss (RL) > 14 dB, and a consistent 90° (±9°) phase deviation. Moreover, the QSFA patches can expand the CP bandwidth and reduce the size of the antenna effectively. Measurement results show that the proposed antenna achieves CP bandwidth of 72% from 1.15 to 2.45 GHz for RL > 10 dB, axial ratio dB, and 3-dB gain variation (gain > 4.4 dBi). Therefore, the proposed antenna is a good candidate for Compass Navigation Satellite System (CNSS) applications.

Journal ArticleDOI
Chul Woo Byeon1, Chul Soon Park1
TL;DR: In this article, a low-loss and high Tx-to-Rx isolation single-pole double-throw (SPDT) millimeter-wave switch for true time delay applications is presented.
Abstract: This paper presents a low-loss and high Tx-to-Rx isolation single-pole double-throw (SPDT) millimeter-wave switch for true time delay applications. The switch is designed based on matching-network and double-shunt transistors with quarter-wavelength transmission lines. The insertion loss and isolation characteristics of the switches are analyzed revealing that optimization of the transistor size with a matching-network switch on the receiver side and a double-shunt switch on the transmitter side can enhance the isolation performance with low loss. Implemented in 90-nm CMOS, the switch achieves a measured insertion loss and Tx-to-Rx isolation of 1.9 and 39 dB at 60 GHz, respectively. The input 1-dB gain compression point is 10 dBm at 60 GHz, and the return loss of the SPDT switch ports is greater than 10 dB at 48-67 GHz.

Proceedings ArticleDOI
04 Mar 2013
TL;DR: In this paper, a probe-based measurement setup is presented that allows the characterization of antennas in the frequency range between 220 GHz and 325 GHz, as well as the gain and the return loss of the antenna under test.
Abstract: In this paper a probe based measurement setup is presented that allows the characterization of antennas in the frequency-range between 220 GHz and 325 GHz The radiation pattern, as well as the gain and the return loss of the antenna under test (AUT) can be measured The limits of the system in terms of accuracy and dynamic range are given To demonstrate its functionality a 240 GHz patch-antenna on Gallium Arsenide (GaAs) substrate is measured A comparison between simulation and measurement shows very good agreement

Journal ArticleDOI
TL;DR: In this paper, a waveguide-to-microstrip transition at millimeter-wave frequencies is proposed, which features two major transformations in sequence: an Eplane probe is chosen to conduct the transformation from waveguide to a suspended line, and a transitional pattern on the printed circuit board is employed to transform the suspended line into a shielded microstrip line.
Abstract: A design for waveguide-to-microstrip transitions at millimeter-wave frequencies is proposed in this letter It features two major transformations in sequence An E -plane probe is chosen to conduct the transformation from waveguide to a suspended line Then, a transitional pattern on the printed circuit board is employed to transform the suspended line into a shielded microstrip line To complete the design, a metallic buffer is introduced for the transformation between the shielded microstrip line and a microstrip line A proposed transition at W-band is presented based on the results from numerical simulations Two of the transitions in back-to-back connection are measured for the purpose of verification The results show that the proposed waveguide-to-microstrip transition can offer the advantages of low insertion loss, good return loss, broadband nature, and stable performance at millimeter-wave frequencies

Journal ArticleDOI
TL;DR: In this paper, two different waveguide-to-microstrip transition designs for the 76-81 GHz frequency band are presented for the integration of multi-channel array systems allowing an element spacing of λ 0/2 or less.
Abstract: This letter presents two different waveguide-to-microstrip transition designs for the 76-81 GHz frequency band. Both transitions are fabricated on a grounded single layer substrate using a standard printed circuit board (PCB) fabrication process. A coplanar patch antenna and a feed technique at the non-radiating edge are used for the impedance transformation. In the first design, a conventional WR-10 waveguide is connected. In the second design, a WR-10 waveguide flange with an additional inductive waveguide iris is employed to improve the bandwidth. Both designs were developed for the integration of multi-channel array systems allowing an element spacing of λ0/2 or less. Measurement results of the first transition without the iris show a bandwidth of 8.5 GHz (11%) for 10 dB return loss and a minimum insertion loss (IL) of 0.35 dB. The transition using the iris increases the bandwidth to 12 GHz (15%) for 10 dB return loss and shows a minimum insertion loss of 0.6 dB at 77 GHz.

Journal ArticleDOI
TL;DR: A modified three-stage UWB LNA with inter-stage inductors with forward Body-Biased technique used to reduce threshold voltage and power consumption at the first and third stages and a push-pull topology exploiting the complementary characteristics of NMOS and PMOS transistors to enhance the linearity performance.

Journal ArticleDOI
TL;DR: In this article, the authors present a technology for the manufacturing of silicon-filled integrated waveguides enabling the realization of low-loss high-performance millimeter-wave passive components and high gain array antennas.
Abstract: We present a technology for the manufacturing of silicon-filled integrated waveguides enabling the realization of low-loss high-performance millimeter-wave passive components and high gain array antennas, thus facilitating the realization of highly integrated millimeter-wave systems. The proposed technology employs deep reactive-ion-etching (DRIE) techniques with aluminum metallization steps to integrate rectangular waveguides with high geometrical accuracy and continuous metallic side walls. Measurement results of integrated rectangular waveguides are reported exhibiting losses of 0.15 dB/ λg at 105 GHz. Moreover, ultra-wideband coplanar to waveguide transitions with 0.6 dB insertion loss at 105 GHz and return loss better than 15 dB from 80 to 110 GHz are described and characterized. The design, integration and measured performance of a frequency scanning slotted-waveguide array antenna is reported, achieving a measured beam steering capability of 82 ° within a band of 23 GHz and a half-power beam-width (HPBW) of 8.5 ° at 96 GHz. Finally, to showcase the capability of this technology to facilitate low-cost mm-wave system level integration, a frequency modulated continuous wave (FMCW) transmit-receive IC for imaging radar applications is flip-chip mounted directly on the integrated array and experimentally characterized.