A microstrip array feed for land mobile satellite reflectorantennas

A circularly polarized feed array for a spacecraft reflector antenna is described that was constructed by using linearly polarized microstrip elements. The array has seven subarrays which form a single cluster as part of a large overlapping cluster reflector feed array. Each of the seven subarrays consists of four linearly polarized microstrip elements. The array achieved a better than 0.8-dB axial ratio at the array pattern peak and better then 3 dB antenna gain to 20° from the peak, across a 7.5% frequency bandwidth. A teardrop-shaped feed probe was used to achieve wideband input impedance matching for the relatively thick microstrip substrate. The low impedance and axial ratio bandwidths were achieved using a relatively thick honeycomb substrate with the impedance-matching feed probes     

一种单馈小型化宽波束双层圆极化微带天线

设计出一种单馈小型化宽波束双层圆极化微带天线,通过选取低介电常数的介质基片,在双层圆形贴片上分别刻四个槽减小天线的尺寸,中心开十字缝增加天线的阻抗带宽,在贴片边切角和贴片的对角线上选择合适的馈电位置实现圆极化,天线尺寸减少37%,天线方向图对称性好,波束宽度大于80°,增益大于5.3 dB。     

Microstrip antenna aperture-coupled to a microstripline

A new technique for feeding printed antennas is described. A microstrip antenna on one substrate is coupled to a microstripline feed on another parallel substrate through an aperture in the ground plane which separates the two substrates. A simple theory explaining the coupling mechanism is presented, as well as measurements of a prototype aperture-fed antenna.     

Micromachined reconfigurable out-of-plane microstrip patch antenna using plastic deformation magnetic actuation

A new reconfigurable out-of-plane microstrip patch antenna is presented. Using micromachining processes, a microstrip antenna designed for operation around 26 GHz is covered with a thin layer of magnetic material and released from the substrate. Application of an external DC magnetic field causes plastic deformation of the antenna at the boundary point where it is attached to the microstrip feed line, resulting in a patch positioned at an angle over the substrate. Frequency and pattern reconfigurability are demonstrated with measurements. Results indicate that versions of this structure may be used to expand or enhance the capabilities of traditional planar arrays.     

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     

Analysis of the annular-ring-loaded circular-disk microstripantenna

A rigorous analysis of the natural resonance frequencies and input impedance characteristics of an annular-ring-loaded (ARL) circular-disk microstrip antenna is presented. Using vector Hankel transforms, the problem is formulated in terms of vector dual-integral equations. Galerkin's method is then used to solve the equations to obtain the resonance frequencies and the current distribution on the conductive patches arising from a probe excitation. Due to the singular nature of the current distribution, the singularity subtraction method has been used to accelerate the convergence of basis function expansions. Experiments for determining resonance frequencies and input impedance characteristics of an ARL circular-disk microstrip antenna with various substrate thicknesses have been made. The theoretical results are in good agreement with the experimental data even when the thickness of the substrate is 0.1 substrate wavelength. It is shown that this theory can be used to analyze some microstrip antennas with an electrically thick substrate, including the analysis of mutual coupling between conductive patches or between the path and the feed of a microstrip antenna     

A novel feed for a multifrequency hybrid resonator antenna

A novel feed technique for a hybrid resonator antenna is proposed and developed. The antenna consists of microstrip-patch radiator and a pair of twin resonator slots. The proposed feed mechanism is based on a new coupling aperture technique, in which a single microstrip feed line is etched on the same side of the substrate as the radiating patches. The patches are coupled to the feed line through a twin slots located in the ground plane. By selecting suitable structure parameters for the slots and the patches, multifrequency operation is obtained. The proposed antenna structure is suitable for the development of large antenna arrays.     

Radiation and scattering characteristics of microstrip antennas onnormally biased ferrite substrates

Radiation and scattering characteristics of microstrip antennas and arrays printed on ferrite substrates with a normal magnetic bias field are described. The extra degree of freedom offered by the biased ferrite can be used to obtain a number of novel characteristics, including switchable and tunable circularly polarized radiation from a microstrip antenna having a single feed point, dynamic wide-angle impedance matching for phased arrays of microstrip antennas, and a switchable radar cross section reduction technique for microstrip antennas. Results are obtained from full-wave moment method solutions for single microstrip antennas and infinite arrays of microstrip antennas. A cavity model solution for a circular patch antenna on a biased ferrite substrate is also presented, to aid in understanding the operation of these antennas     

Wideband stacked SSFIP patch antenna for SAR applications

A dual-polarised aperture-coupled microstrip stacked patch antenna with stacked feed lines is presented. The antenna is capable of operating over a bandwidth of 30% with improved front-to-back ratio performance. The patches are excited through non-resonating crossed slots. The feed lines are separated by a thin substrate to enhance the port decoupling. The measured impedance and radiation pattern of the antenna at C-band are presented.     

多层微带贴片天线单元和阵列设计

该文通过结合经验公式和全波分析法,设计了一种电容补偿双层贴片、四层介质的微带贴片天线单元,该单元天线在频率为995～1125MHz的范围内,在驻波比SWR1.5的情况下,相对阻抗带宽达到12.26％的工程要求。此外,该文给出由该单元天线组成的216天线阵以及天线阵的驻波比的实测结果,最后给出天线阵的各单元排列方式和单元之间的互耦特性曲线的实测结果。     

Input impedance of a probe-fed circular microstrip antenna with thick substrate

A method of computing the input impedance for the probe fed circular microstrip antenna with thick dielectric substrate is presented. Utilizing the framework of the cavity model, the fields under the microstrip patch are expanded in a set of modes satisfying the boundary conditions on the eccentrically located probe, as well as on the cavity magnetic wall. A mode-matching technique is used to solve for the electric field at the junction between the cavity and the coaxial feed cable. The reflection coefficient of the transverse electromagnetic (TEM) mode incident in the coaxial cable is determined, from which the input impedance of the antenna is computed. Measured data are presented to verify the theoretical calculations. Results of the computation of various losses for the circular printed antenna as a function of substrate thickness are also included.     

一种宽轴比带宽L频段圆极化贴片天线

圆极化全向天线由于其自身的性能特点,在现代无线应用中越来越受到广泛的关注。提出一种宽轴比带宽的L频段圆极化微波贴片天线,该天线有上下两个介质层,下层微带馈线耦合馈电,接地面蚀刻十字交叉缝隙以帮助实现圆极化和改善上层贴片的耦合度。设计结果显示,该天线3dB轴比带宽可以达到3．5％（1.0231．060GHz）,在有效带宽内天线增益高于5．68dBi,在中心频率点（1．04GHz）天线的前后瓣比高于20dB。     

Circular-disk microstrip antenna with an air gap

The circular-disk microstrip antenna with an air gap between the substrate and the ground plane is analyzed using the cavity-model theory. A simple formula for the resonant frequencies is obtained. The internal fields, the radiation fields, the effective loss tangent, and the input impedance are derived when the antenna is provided with a coaxial feed. The theory predicts that the air gap does not alter the relative field patterns significantly but it provides a simple parameter by which the resonant frequencies of the antenna can be tuned. Measurements have been performed on a 5 cm circular-disk microstrip antenna with an air gap and good agreement between theory and experiment is obtained.     

Increasing the bandwidth of a microstrip antenna by proximity coupling

The letter presents experimental results for a proximity-coupled microstrip patch antenna capable of 13% bandwidth. The impedance match (VSWR ? 2), copolarised radiation patterns and crosspolarised radiation were measured over this bandwidth to confirm operation. The construction is quite simple, consisting of a microstrip feedline on a substrate proximity-coupled to a rectangular microstrip patch on a covering superstrate; a small open-circuit tuning stub is connected in shunt with the feed line.     

一种RFID小型圆极化四臂螺旋天线

设计了一种用于UHF频段射频识别系统的小型右手圆极化四臂螺旋天线。天线由印制在微带介质板的4个长条形臂组成,通过微带功分器馈电。天线在进行4个端口的单独匹配和功分器相连时,需采用一种新的匹配方法。通过仿真优化,天线尺寸为60 mm×60 mm×6 mm,峰值增益为3.8 dB,带内轴比＜3 dB,3 dB波束宽度＞120°,前后比＞15 dB。实物测试结果与仿真结果吻合。     

A Compact Broadband H-Slot and Horizontal H-Slot Patch Antenna for Circular Polarization

This paper presents the design of compact broadband H-slot and horizontal H-slot microstrip patch antenna with a single feed. The antenna is also used for circular polarization application with a single narrowband frequency. The performance of single feed notched and truncated corner circularly polarized microstrip antennas with the same substrate thickness for H-slot and horizontal H-slot is studied. The simulated results such as return loss S₁₁, axial ratio AR, radiation pattern (E_left and E_right), and gain are presented in this paper for different shapes of patch antenna.     

一种新型宽带印制天线

本文给出了一种新型双偶极子型宽带印制天线,并设计出相应的类平行宽边耦合双线双面馈电结构。采用矩量法求解积分方程进行理论分析,由此设计出一种新型宽带印制天线,并进行实验测试。理论分析表明：在相同的基片上,双偶极子型印制天线比普通微带振子天线的带宽宽得多;同时实测结果表明：在0.8mm的介质基片上,工作于中心频率2GHz的该新型天线带宽可达23％（VSWR＜2.0）,增益达4.3dBi。该宽带天线为平面印制结构,易于与电路集成,亦可做为天线阵元,成本低,性能好。     

近场聚焦微带阵列天线研究

设计了一个近场聚焦(NFF[1] )环形微带阵列天线,环上的微带贴片单元均采用同轴线馈电,工作频 率为2. 45GHz。该天线通过控制相邻两个环之间的距离,使相邻两环上的微带单元到达焦点的距离相差一个波长来 实现聚焦,继而探讨了调节两圆环之间的距离和增加圆环数目对焦斑尺寸的影响。利用HFSS 和CST 等电磁仿真软 件对天线进行仿真,并做出实物进行测试,仿真和测试结果表明:环形微带阵列天线可以很好地实现聚焦,并且随着 两环之间距离的减小和圆环数目的增多,焦斑的尺寸越来越小,从而实现在微波热疗等领域的应用。     

Scattering from a microstrip patch

A solution to the problem of plane wave scattering by a rectangular microstrip patch on a grounded dielectric substrate is presented. The model does not include the microstrip feed, and thus does not include the so-called "antenna mode" component of the scattering. The solution begins by formulating an electric field integral equation for the surface current density on the microstrip patch. The integral equation is solved using the method of moments. Computed data for the patch radar cross section (RCS) is found to be in close agreement with measurements over a broad frequency range. The microstrip RCS versus frequency consists of a number of large peaks which are identified as impedance or pattern factor resonance peaks.     

Microstrip antennas on synthesized low dielectric-constantsubstrates

Micromachining techniques using closely spaced holes have been used underneath a microstrip antenna on a high dielectric-constant substrate (ϵ_r=10.8) to synthesize a localized low dielectric-constant environment (ϵ_r=2.3). The measured radiation efficiency of a microstrip antenna on a micromachined 635-μm thick ϵ_r=10.8 Duroid 6010 substrate increased from 48±3% to 73±3% at 12.8-13.0 GHz (including 3.3-cm feed line losses). We believe that this technique can be applied to millimeter-wave antennas (microstrip, dipoles, slots, etc.) on silicon and GaAs substrates to result in relatively wideband (3-6%) monolithic microwave integrated circuits (MMIC) active antenna modules for phased-arrays and collision-avoidance systems