Broadband dual-polarised antenna with high isolation for wireless communication

A broadband dual-polarised antenna with four end-to-end folded dipoles and a U-shaped ground is presented. Stable and symmetric radiation patterns at slanted ±45° polarisation have been obtained within the band 1.71?2.17 GHz. Measurements show two linear polarisations with an isolation of more than 30 dB over the operating frequency band. A return loss less than 214 dB is achieved and the measured cross-polar level is 23.5 dB below the co-polar level within the above-mentioned band.     

Wideband uniplanar 180° phase switch

A wideband 180° phase switch is developed at millimetre-wave frequencies (31 GHz centre frequency) using uniplanar technology. The circuit is designed using coplanar-to-slotline transitions and commercial pin diodes as switching devices. The implementation is straightforward, fast in terms of fabrication and low-cost. The circuits tested, made on an alumina substrate, show a phase difference between states of 180° ± 2°, providing 40% bandwidth with in-band insertion loss lower than 2.5 dB and a return loss better than 10 dB. The phase switch provides a ±5° phase error in a bandwidth of around 60%, from 18 to 38 GHz.     

Passive broadband millimetre-wave uniplanar MMIC balun

A new uniplanar monolithic microwave integrated circuit (MMIC) balun using lumped circuits is presented. The proposed planar balun consists of a wideband Wilkinson power divider and a broadband 180° phase shifter using novel series and parallel LC reflective terminating circuits. To demonstrate the design methodology, a 24?44 GHz MMIC balun was realised as a 1.4 mm _{GaAs chip. The measured return losses for the unbalanced and balanced ports are better than 212, 210 and 27 dB, respectively. The measured amplitude and phase imbalance between the two output ports are less than 0.5 dB and 7°, respectively, and maximum insertion loss is 5 dB.}     

0.18 μm 21-27 GHz CMOS UWB LNA with 9.3 ± 1.3 dB gain and 103.9 ± 8.1 ps group delay

A 21-27 GHz CMOS ultra-wideband low-noise amplifier (UWB LNA) with state-of-the-art phase linearity property (group delay variation is only ± 8.1 ps across the whole band) is reported for the first time. To achieve high and flat gain (S₂₁) and small group delay variation at the same time, the inductive series peaking technique was adopted in the output of each stage for bandwidth enhancement. The LNA dissipated 27 mW power and achieved input return loss (S₁₁) of 213 to 220.1 dB, output return loss (S₂₂) of 28.2 to 230.2 dB, flat S21 of 9.3 ± 1.3 dB, reverse isolation (S₁₂) of 252.7 to 273.3 dB, and noise figure of 4.9?6.1 dB over the 21-27 GHz band of interest. The measured 1 dB compression point (P_1dB) and input third-order intermodulation point (IIP3) were 214 and 24 dBm, respectively, at 24 GHz.     

Wideband Circularly Polarized Vertical Patch Antenna

A compact circularly polarized (CP) vertical patch antenna is presented that employs a microstrip to slot-line transition for a wideband operation. The antenna is composed of two vertical patches, which are shaped as helix to obtain a broadband CP performance. The loop structure and the vertical overlap configuration lead to significant size reduction as much as 48% when compared to that of the printed dual-loop antenna. Simulated results agree well with the measurement, showing that the antenna possesses a wide axial ratio $({rm AR}≪ 3~{rm dB})$ bandwidth of 28.5%, and a broad return loss $(S _{11} ≪ -10~{rm dB})$ bandwidth of 37.8%. Also, it has symmetric radiation patterns and low cross-polarization levels in the broadside direction over the operating bandwidth. Moreover, the antenna gain is around 8 dBi, and it is very stable across the operating bandwidth.      

Linearly polarised radial stub fed high performance wideband slotantenna

A wideband printed slot antenna fed by a radial stub operating over the mobile communication bands PCN (1.716-1.880 GHz) and UMTS (1.9-2.0 GHz and 2.1-2.2 GHz) is presented. The impedance bandwidth of the antenna achieved for a VSMR⩽2 is 34% and the radiation patterns remain stable over the entire frequency band of operation (1.7-2.4 GHz) with cross-polarisation levels of less than -20 dB. Simulated and measured radiation pattern and return loss results are presented     

60 GHz compact integrated cross-coupled SIR-MH bandpass filter on bulk CMOS

A new 60 GHz fourth-order cross-coupled bandpass filter using a step- impedance-resonator (SIR) miniaturised open-loop resonator and the miniaturised-hairpin (MH) resonator was designed and fabricated on 0.13 mum bulk CMOS. It has 8.5 GHz (58-66.5 GHz) bandwidth, 5.9 dB insertion loss, and better than 10 dB return loss over the whole passband, and exhibits high selectivity and a compact size of 714.9 times 484 mum (0.346 mm ). This filter is the first reported cross-coupled filter above 40 GHz on CMOS.     

X波段交直流分离的MEMS开关的设计与研究

介绍了一种带直流驱动电极交直流分离的MEMS开关,研究了影响开关阈值电压的因素,运用缩腰设计、尺寸优化等方法降低开关的阈值电压;运用阻抗匹配方法降低开关的反射损耗;利用等效电感的设计提高所需频段的隔离度。使用Coventor和HFSS软件模拟,设计的开关阈值电压小于20V,在X波段插入损耗低于0.1dB,反射损耗低于-25dB,谐振点处隔离度高于40dB。     

A 60–110 GHz Transmission-Line Integrated SPDT Switch in 90 nm CMOS Technology

This letter demonstrates a fully integrated transmit/receive single-pole-double-throw switch in standard bulk 90 nm CMOS process. This switch is based on the transmission-line integrated approach that reduces the effect of parasitic capacitance of transistors in the desired band, and this approach can achieve good isolation and return loss with fewer stages of transistors and broad bandwidth. The switch provides an insertion loss of 3–4 dB and a return loss better than 10 dB in 60–110 GHz. The measured isolation is better than 25 dB. The measured 1 dB compression point of input power is 10.5 dBm at 75 GHz. To the best of our knowledge, this is the first CMOS switch operating beyond 100 GHz.      

一种新型波束可控的口径耦合天线

设计一种基于人工电磁结构（AMC）的新型口径耦合天线。对加载了AMC 结构的口径耦合天线进行仿真。 根据仿真结果,天线的工作频率为5.5GHz,辐射的波束指向21°时增益为6.4dB。文中对天线的参数进行分析,波束 的偏移角度与AMC 结构的有关。将AMC 结构变为一排,天线波束可以指向11°。根据天线单元构造1×2 的子阵, 阵列天线具有更高的增益和带宽,并可以有波束的偏移。 天线子阵工作在5.5GHz 时天线的波束指向为26°,增益 8.47dB。     

Miniaturised broadside coupler using coupled slow-wave artificial lines

A miniaturised broadside coupled-line coupler is presented. The coupler is fabricated on a six-layered printed circuit board and consists of a 90° coupled slow-wave artificial transmission line section. Compared with previous works on printed circuit boards, the proposed design features the smallest occupied size. It also demonstrates a comparable operating bandwidth of 85%. The design concept, methodology and results are investigated.     

Design of electrically small, folded monopole antenna using C-shaped meander for active 433.92 MHz RFID tag in metallic container application

A miniaturised RFID tag antenna for an active 433.92 MHz RFID system was designed, fabricated and measured. To attain a low profile, a folded monopole was bent and matched with a stub like an inverted-F antenna. Then the horizontal radiating segment was miniaturised with a C-shaped meander. The height of the antenna from the ground plane was 20 mm (0.029λ) and the antenna can be enclosed in a circle with a diameter of 34 mm (0.049λ). The measured 210 dB fractional bandwidth was 3.52 MHz (0.81%) and the measured gain showed a conical radiation pattern with a maximum gain of 21.33 dBd.     

基于人工磁导体的芯片内/芯片间无线互连单极子天线传输特性研究

提出了一种新的用于芯片内/芯片间无线通信系统中的基于人工磁导体（Artificial Magnetic Conductor,AMC）结构的单极子管脚天线阵列模型.印刷电路板（Printed Circuit Board,PCB）采用厚度3mm的FR4介质,形状为边长50mm正方形.4个单极子天线分布在PCB基板中心15mm×15mm的正方形各顶点上,代表4个芯片的4个管脚.天线为铜材质,长度2.6mm,直径1.5mm.在PCB介质中嵌入了一个周期性人工磁导体铜质平面,4个单极子天线形成一个4端口网络.在仿真基础上,进了实物加工测试.实测结果表明,具有AMC的天线阵列回波损耗（S₁₁）-10dB频带为13.02GHz~15.73GHz;在14.22GHz处,S₁₁的幅度达到最小值-27.25dB,S₂₁、S₃₁、S₄₁分别为-26.26dB、-19.23dB、-21.14dB.与不含AMC结构的天线阵列相比,S参数得到了有效改善,其中S₁₁改善了约3.63dB,S₂₁、S₃₁、S₄₁分别提高了2.05dB、7.21dB、5.28dB.验证了在PCB介质中嵌入AMC结构,可以有效提高单极子天线间的电压传输系数,增加信号的功率传输增益.     

A New High-Gain Microstrip Yagi Array Antenna With a High Front-to-Back (F/B) Ratio for WLAN and Millimeter-Wave Applications

A new printed microstrip Yagi array antenna is proposed that can achieve a high gain and low backside radiation for various applications up to the millimeter-wave frequency range. The high front-to-back (F/B) ratio (up to 15 dB) is attributed to the constructive interference that takes place between the individual printed Yagi arrays in the design. Through the spacing of the elements, the directivity (between 9-11.5 dBi) and the F/B ratio can be altered to suit the application of interest. The operational principles of this design are discussed to give insight on the radiation mechanism of the antenna. An initial design at around 32.5 GHz is presented to show the performance capabilities of this configuration. An impedance bandwidth of 8.3% can be achieved around this frequency. Then, a parametric analysis is conducted to estimate the significance of the design parameters that affect the antenna's performance. Finally, measured return loss and radiation pattern performance at 5.2 GHz is displayed to validate the principles and simulated results of the design. The measured impedance bandwidth of 10% is achieved. The F/B ratio is 15 dB which is larger than values previously published by 5-10 dB. Additionally, a gain of 10.7 dBi is observed. To the author's knowledge, this is the first microstrip Yagi array antenna presented that has a high gain and a high F/B ratio designed using simple fabrication techniques     

Coplanar-waveguide/microstrip probe coupler and applications to antennas

A method to couple microwave power from a coplanar waveguide to a microstrip line on opposite sides of a ground plane is demonstrated. The measured insertion loss and return loss are about 1 dB and 10 dB, respectively, across the frequency range of 0.045-6.5 GHz. To demonstrate potential applications of the coupler as a feeding network for a microstrip patch array measured radiation patterns for two rectangular patch antennas with a direct coplanar-waveguide/microstrip feed and with a proximity coupled coplanar-waveguide/microstrip feed are presented.<>     

Wideband and small size star-shaped microstrip patch antenna

A new wideband and small size star-shaped patch antenna, fed by a small rectangular patch, is proposed. Simulation via a finite element program and measured results of return loss, and the E- and H-plane radiation patterns of the proposed antenna, are presented. The antenna is able to achieve in the range 5-9.3 GHz an impedance bandwidth of 63% for return loss of less than -10 dB     

Broadband coplanar waveguide-coplanar strip-fed spiral antenna

A novel broadband coaxial-coplanar waveguide-coplanar strip-fed spiral antenna is presented. The antenna has good radiation patterns and a return loss of better than 10 dB over a wide bandwidth from 0.4 to 3.6 GHz. A DC-3.7 GHz broadband balun was developed for the antenna feed     

Ultrabroadband printed (UBP) antenna

An ultra broadband printed (UBP) antenna is presented which consists of a diplexer and two aperture stacked patch antennas. S-parameter theory is used to investigate the input impedance behavior of the UBP antenna. This antenna can produce a 10-dB return loss bandwidth of almost 120% with constant gain of 6.5 dB. A relatively uniform radiation pattern over the entire band was also achieved.     

Radiation performance improvement of wideband microstrip antenna array using wideband AMC structure

In this paper, the radiation performance of an antenna array is improved by designing a new wideband artificial magnetic conductor (AMC). The proposed AMC surface operates at the frequency of 3 GHz with ±90^° reflection phase bandwidth of 22%. In order to identify the key design parameters of the AMC structure, a parametric study is performed. To improve the radiation performance of the antenna array, an AMC reflector is developed through utilizing an array of 2 × 8 periodic patches of AMC unit cells. By this technique, the front to back ratio of the designed antenna array is enhanced about 16.27 dB. It is concluded that tuning of the AMC dimensions for controlling the reflection coefficient at each port of antenna array during beam steering is necessary. Because of the using of the AMC surfaces as a reflector instead of conventional PEC surfaces, size reduction of the antenna array in the order of 20% is achieved. In this study, a circuit model for single element of the antenna array with considering AMC loading effect is introduced, which predicts the bandwidth behaviour of the proposed antenna. The final designed antenna array exhibits low level of cross polarization making it well‐suited for tracking radars and electronic warfare applications. The proposed antenna with the AMC reflector is fabricated and measured. The measured ?10 dB impedance bandwidth and peak gain of the proposed antenna is 20% (2.7‐3.25 GHz) and 13.4 dBi, respectively, which are compatible with the simulation results.     

A 94-GHz aperture-coupled micromachined microstrip antenna

This paper presents an aperture-coupled micromachined microstrip antenna operating at 94 GHz. The design consists of two stacked silicon substrates: (1) the top substrate, which carries the microstrip antenna, is micromachined to improve the radiation performance of the antenna and (2) the bottom substrate, which carries the microstrip feed line and the coupling slot. The measured return loss is -18 dB at 94 GHz for a 10-dB bandwidth of 10%. A maximum efficiency of 58±5% has been measured and the radiation patterns show a measured front-to-back ratio of -10 dB at 94 GHz. The measured mutual coupling is below -20 dB in both E- and H-plane directions due to the integration of small 50-μm silicon beams between the antennas. The micromachined microstrip antenna is an efficient solution to the vertical integration of antenna arrays at millimeter-wave frequencies