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.<>     

一种基于折合式平面反射阵天线的毫米波高增益滤波天线

提出了一种基于折合式平面反射阵天线的毫米波高增益滤波天线设计方法,将极化敏感的频率选择表面替代传统的极化栅,用作折合式平面反射阵天线的副反射面.基于基片集成波导技术设计了极化敏感的频率选择表面,该频率选择表面对于线性极化入射波情况下具有较低的插入损耗,同时可几乎全反射对应正交极化的入射波.得益于频率选择表面的频率选择特...     

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     

低损耗双模微带贴片带通滤波器研究

首先提出了一种新颖、简单的带有两个切角的双模微带带通滤波器结构。该结构使用单个贴片谐振器并且没有耦合缝隙,通带两端各有一个衰减极点,可以有效减小滤波器的辐射损耗。对该滤波器结构进一步改进,又提出了一种中心频率1.8GHz相互正交槽线的新型双模微带带通滤波器结构。该滤波器在中心频率1.8GHz处,回波损耗达到31.65dB,通带内最小插损为0.01dB,3dB带宽为19.44%。研究结果表明该结构可以进一步减小辐射损耗,并且可以减小滤波器的体积,有利于小型化。     

Shorting strap tunable single feed dual-band PIFA

RF switches are integrated to the shorting straps of a single feed dual-band planar inverted-F antenna (PIFA) to make a tunable PIFA. The L-band switch yields 0.45-dB insertion loss (IL) and 10-dB isolation bandwidth (BW) of 40% at 1.5 GHz. The tunable PIFA yields 39% impedance BW at 900-MHz band and 7.8% BW at 2000-MHz band. The measured radiation patterns are nearly omni-directional and yield a gain of -7.8 dBi at 652 MHz and 4.3 dBi at 2104 MHz.     

High-performance filtering power divider based on air-filled substrate integrated waveguide technology

A filtering power divider based on air-filled substrate-integrated waveguide (AFSIW) technology is proposed in this study. The AFSIW structure is used in the proposed filtering power divider for substantially reducing the transmission losses. This structure occupies a large area because of the use of air as a dielectric instead of typical dielectric materials. A filtering power divider provides power division and frequency selectivity simultaneously in a single device. The proposed filtering power divider comprises three AFSIW cavities. The filtering function is achieved using symmetrical inductive posts. The input and output ports of the proposed circuit are realized by directly connecting coaxial lines to the AFSIW cavities. This transition from the coaxial line to the AFSIW cavity eliminates the additional transitions, such as AFSIW-SIW and SIW-conductor-backed coplanar waveguide, applied in existing AFSIW circuits. The proposed power divider with a second-order bandpass filtering response is fabricated and measured at 5.5 GHz. The measurement results show that this circuit has a minimum insertion loss of 1 dB, 3-dB fractional bandwidth of 11.2%, and return loss exceeding 11 dB.     

Use of the Dielectric Resonator Antenna as a Filter Element

For the first time, the dielectric resonator antenna (DRA) is simultaneously used as a filtering device, named as the DRA filter (DRAF). The theory and design methodology of the DRAF are elucidated using the cylindrical DR. It was found that the operating frequency of the filter part can be made equal to, or different from, that of the antenna part. The return loss, input impedance, radiation patterns, and insertion loss of the DRAF are studied. To improve the insertion loss of the filter part, the DR is top-loaded by a metallic disk without significantly affecting the radiation efficiency of the antenna part. The disk, in addition, can be used to tune the frequency of the filter. It was found that the antenna and filter parts of the DRAF can be designed and tuned almost independently. A second-order DRAF is also designed in this paper. As the dual function DRAF is compact and cost effective, it should find applications in modern wireless communication systems.     

一种新型复合结构的四分之一波长带通滤波器

提出了一种基于共面波导(Coplanar Waveguide,CPW)和微带线复合结构的四分之一波长带通滤波器(Bandpass Filter,BPF)。该带通滤波器由两个终端开路的T形微带馈线结构和四个交叉耦合的四分之一波长CPW谐振器组成。通过仿真优化得到其特性曲线图,并分析比较了不同参数对其滤波性能的影响。仿真结果表明,该带通滤波器在其2.97～3.03 GHz的通带内的最小插损低于0.4dB,回波损耗大于30dB,同时其带外衰减都大于25dB。这种滤波器结构紧凑,尺寸小,性能好,可应用于很多微波系统中。     

A broadband transition between microstrip and coplanar stripline

A design for a broadband microstrip-to-coplanar-stripline transition using broadside-coupled strips is proposed in this letter. Two transitions are designed in back-to-back configuration and the insertion loss is optimized in X-band (8.2 GHz/spl sim/12.4 GHz). Both simulation and measurement are in good agreement. The measured bandwidth for 1 dB insertion loss and 20 dB return loss is from 6.9 GHz to 12.4 GHz.     

The Measurement of the Radiation Losses in Dielectric Image Line Bends and the Calculation of a Minimum Acceptable Curvature Radius

Measurements of the insertion loss due to radiation curved dielectric image lines of rectangular cross section are described for the frequency range from 26 to 90 GHz. A minimum acceptable curvature radius as a function of the frequency is calculated employing the field distributions of straight dielectric image lines and is compared with measurements.     

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     

A vertically integrated micromachined filter

A 10-GHz filter constructed of slot-coupled micromachined cavities in silicon is presented. The novel character of the filter lies in its structure, which consists of a microstrip feed to cavities via slot apertures and three vertically stacked slot-coupled cavities. The cavities are essentially reduced-height waveguide resonators. The measured results are presented and compared to a finite-element-method model. The simulated model has a bandwidth of 4% with an insertion loss of 0.9 dB at 10.02 GHz. The measured filter yields a 3.7% bandwidth with a deembedded insertion loss of 2.0 dB at 10.01 GHz. Various loss mechanisms are examined to explain the difference between simulated and measured insertion loss     

Crumpled textile antennas

The performance of a dual-band textile antenna under two-dimensional crumpling conditions is described. Both input impedance and radiation patterns are investigated based on numerical and experimental methods at 2.45 and 5.8 GHz. The return loss for the coplanar antenna is affected by the most severe crumpling at the higher frequency band, while the radiation patterns remain acceptable at both bands.     

一种基于石英玻璃衬底的MEMS阶跃交指滤波器

提出了一种基于石英玻璃衬底的MEMS 5阶交指滤波器。利用三维全波电磁仿真软件CST,对设计的5阶交指滤波器进行结构优化和数值仿真。结果表明,该滤波器的中心频率为4.08 GHz,带内插损小于1.5 dB,带宽为1.21 GHz,大于基于硅衬底的7阶交指滤波器的0.8 GHz带宽。该方案减小了交指滤波器的尺寸,增加了带通滤波带宽,提高了滤波性能。讨论了硅、氮化硅、氮化硼和高硼硅玻璃等衬底材料与低阻抗长度对滤波器性能的影响,理论验证了低功耗、宽频滤波的5阶交指滤波器的性能。结果表明,石英玻璃衬底具有最佳的综合性能。     

Compact dual-band antenna for wireless access point

A compact dual-band printed antenna covering the 2.4 GHz (2400-2485 MHz) and 5.2 GHz (5150-5350 MHz) WLAN bands is presented. The experimental analysis shows a 2:1 VSWR bandwidth of up to 32 and 8% for 2.4 and 5.2 GHz, respectively. The measured radiation patterns are nearly omnidirectional, with moderate gain in both the WLAN bands.     

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     

宽频带高插损电源滤波器的研制

军标认证测试对传导辐射有严格的要求,针对低辐射保密机柜传导超标的问题,设计了一种宽频带高差损滤波器.该滤波器能在9 kHz～1 GHz频段上提供超过80 dB的共模插入损耗,有效抑制了传导辐射.从设计原理、结构和材料选择上分别进行了阐述,并对实物进行了测试.测试结果表明该滤波器的研制符合设计需求.     

Performance improvement and size reduction of microstrip dual-mode bandpass filter

A novel miniaturised dual-mode bandpass filter with multi-arc resonators is proposed. The size of the dual-mode filter can be reduced significantly by using the microstrip dual-mode resonator consisting of multi-arcs; meanwhile insertion loss and spurious response suppression are improved A prototype filter is designed and implemented at 3.6 GHz with 2.8% fractional bandwidth, which shows a low passband insertion loss of 1.02 dB and a wide stopband with rejection better than 20 dB up to about 8.5 GHz.     

MEMS-Switched Parasitic-Antenna Array for Radiation Pattern Diversity

A micro-electro-mechanical series (MEMS)-switched parasitic antenna array providing radiation pattern diversity is described. A new modeling method is introduced in order to allow a fast and accurate optimization of the antenna. This method is demonstrated with the design of both passive and active prototypes at 5.6 GHz. The active prototype makes use of stand-alone packaged MEMS switches. Measured return loss and radiation patterns are in good agreement with the design, demonstrating a beam-switching at$pm 25^circ$.