X波段二维宽带宽扫背腔微带天线

设计了一种X波段背腔微带天线,采用探针和口径耦合相结合的馈电方式实现了小单元间距下单层微带贴片的宽带工作,并弱化了馈线寄生辐射对方向图的扰动。设计加工了8×8单元的天线小阵。实测结果表明,该天线在设计要求的2GHz带宽内驻波小于1.5,驻波小于2的相对带宽25%;方向图测试结果表明实现了方位向45°、俯仰向30°的扫描,增益22.8dB,天线效率大于80%,可满足二维宽带宽扫瓦片天线的实际应用需求。     

基于双负材料的宽频带微带天线设计

采用空腔模型法设计了以双负材料(ε、μ为负值)为介质衬底的新型微带天线。实物测试表明:新型天线比普通材料微带天线明显展宽带宽。在未对天线贴片作优化处理的情况下,新型天线–10 dB反射系数带宽达1.50 GHz,比普通材料的天线展宽约70%,相对带宽达16.3%,E面辐射方向图较前者偏转了约40°,而H面方向图则与普通材料天线相似。     

一种X波段宽带背腔微带天线阵面设计

文章介绍了一种X波段宽带、宽扫、背腔式微带天线阵面。该天线利用背腔式口径耦合馈电的方式使单层微带板贴片单元实现了阵面中小单元间距下天线的宽带性能,并结合探针式天线单元级独立馈电的方法,实现了天线阵面的大角度扫描功能。基于项目需求,设计加工了一套8×8单元天线阵面,测试结果表明:该天线在X波段21%的相对带宽内驻波优于1.8,可在方位向实现±45°的大角度扫描,天线效率达到了80%以上,满足了项目的电性能指标要求。     

基于微带天线的带宽展宽方法研究

微带天线是一种典型的窄频率带宽天线,在高频情况下尤其如此。在本文中,使用了微带天线的两个模来计算矩形微带天线的输入阻抗。通过使用TE0 1模和TM 01模,在更高的介电常数下计算,相关带宽可以从0.7%增长到2.7%。同时给出仿真结果。     

微带天线带宽及模式特性研究

微带天线具有剖面低、重量轻、易于与平台共形等优点,传统微带天线带宽较窄,目前已有一些方法 来展宽微带天线带宽。然而,设计中发现,展宽微带天线带宽的同时可能会出现高次模,高次模的出现导致天线方 向图的恶化,而目前这方面研究还较少。本文基于线极化微带天线模型,对影响天线带宽的因素和天线高次模出现 的条件进行了分析,得到以下结论:为了增加天线带宽,应选用小介电常数的介质板,同时增加天线和反射板之间的 距离并增加天线宽度;通过对微带天线模式特性进行分析可知,若天线较宽,为了抑制高次模的出现,天线高度h 应 小于0. 15λ0 ,随着天线的变窄,这一限制逐渐变小。     

基于HFSS多层宽带微带天线仿真设计

采用HFSS10电磁场仿真软件设计和仿真了一种宽频带多层微带贴片天线.天线采用双辐射贴片系统,同时利用正方形金属电容片补偿由于馈电探针引入的电感,从而获得了比较宽的工作带宽.该天线仿真的驻波比VSWR≤2时的阻抗带宽达到了25%,覆盖了1.4GHz～1.8GHz的频率范围.且仿真结果表明该天线还具备了良好的宽波束和高增益特性,天线的半功率波束宽度在100度左右,在两个谐振频率点1.45GHz和1.75GHz处的最高增益分别为9dB和10dB,与理论计算的值有很好的一致性.结果也说明了HFSS软件的可靠性和高效性.     

带反射背腔的圆形缝隙天线的仿真与设计

平面宽缝天线具有全向辐射,中等增益等特点,是最具吸引力的平面宽带候选天线之一.平面宽缝天线具有不同的缝隙形状,如矩形,圆形,弧形;具有不同的馈电形状,如T形,十字形,叉状,蝴蝶结形,星形枝节,π形,双T形,圆形,矩形等.仿真和设计了一款带圆柄的微带线馈电的宽带圆形缝隙天线,并通过添加带多调谐结构的反射背腔使天线获得了良...     

基于背腔结构的瓦片式两维有源相控阵天线

本文提出了一种低剖面宽带平面相控阵天线,该天线工作于X波段并且具有两维宽角扫描特性.采用了瓦片式子阵模块为集成架构,并且以背腔结构的多层微带天线作为阵列单元.基于仿真设计结果,加工了一个8×8平面相控阵样机.实测结果表明,所提出的阵列在8～12 GHz频率范围内,H面最大扫描角为±45°、E面最大扫描角为±30°.因此...     

一种高介GPS微带天线的设计与研究

针对传统GPS天线体积较大的问题,提出了一种改进的圆极化微带贴片天线,该天线用高介电常数的陶瓷作为天线基板,采用单端口背馈方式馈电,缩小了天线尺寸,结构简单。通过仿真优化,获得了比较好的阻抗带宽和轴比带宽,并以此为基础研究了介质基板厚度及损耗对天线性能的影响,为GPS微带天线设计提供一种思路。     

Single and stacked circular microstrip patch antennas backed by acircular cavity

In this communication, a full wave moment method solution for a probe-fed circular microstrip patch antenna, backed by a circular cavity both in single and in stacked configurations, is used to analyze the effect of a parasitic patch on antenna bandwidth. In addition, the effect of recessing a single patch into the antenna cavity is studied. In both cases, theoretical results for the scattering and radiation characteristics of the antenna are presented     

左手媒质基片微带天线的特性研究

将离散复镜像方法推广到左手媒质基片的格林函数计算中,并应用矩量法对左手媒质基片微带天线的辐射特性进行了研究.这种新型天线在左手媒质基片负介电常数的绝对值小于或等于负磁导率绝对值时,可以得到与传统微带天线相类似的方向图;而在负介电常数的绝对值远大于负磁导率的绝对值时,所得到的方向图具有主瓣宽度窄,仰角低的特点.针对这一全新的辐射特性,提出了左手媒质基片微带天线作为高指向性天线的应用.     

Analysis of arbitrarily shaped coax-fed microstrip antennas with thick substrates

Arbitrarily shaped, coax-fed microstrip patch antennas with thick substrates are studied using a mixed-potential integral equation approach. This incorporates a triangle-element model of the patch and a rigorous treatment of the probe-to-patch junction. Computed input impedance data are shown to agree well with measured results.<>     

An experimental study of microstrip antennas on very highpermittivity ceramic substrates and very small ground planes

An experimental study of rectangular microstrip antennas on two ceramic composite substrates, barium-titanate with a dielectric constant of 37 and neodymium-titanate substrates with a dielectric constant of 85, is presented. The measured results for radiation patterns, cross-pol levels and resonant frequencies for antennas with ground planes as small as 1"×1" are given. It is shown that, for very small ground planes, the far-field pattern is smooth and nearly omnidirectional in both E and H planes, a feature that may be of interest in many mobile applications     

Circularly polarized rectangularly bent slot antennas backed by arectangular cavity

Rectangularly bent slot antennas backed by a rectangular cavity for circular polarization are proposed. Characteristics of three types of cavity-backed rectangularly bent slot antennas for circular polarization-the single square loop slot, the two-element square loop slot, and the two-arm square spiral slot antenna-are analyzed numerically. The generalized network formulation based on the equivalence principle is given in terms of the method of moments. The magnetic currents on the thin rectangularly bent slots in the presence of the backing cavity are obtained and used to calculate the input impedance, radiation pattern, and axial ratio. Experimental results on the input impedance, radiation pattern, and axial ratio are in good agreement with calculated data     

Characteristics of aperture coupled microstrip antennas on magnetized ferrite substrates

The method of moments in the spectral domain is applied to the full-wave analysis of aperture coupled microstrip antennas in the case where the substrate of the antennas is a layered medium containing magnetized ferrites. The subsectional basis functions used in the analysis make it possible to handle patch antennas and coupling apertures with right angle corners of arbitrary shape. The numerical results obtained show that antennas on ferrite substrates fed by single microstrip lines can radiate both circular and linear polarization, the polarization state being dependent on the orientation of the ferrites bias magnetic field. For a given polarization state, the matching frequency band of the antennas can be tuned over a wide frequency range by adjusting the magnitude of the bias magnetic field. Also, the polarization state can be continuously tuned from circular to linear within the same frequency band by adjusting both the magnitude and the orientation of the bias magnetic field. Some measurements are presented in order to check the validity of the numerical algorithm developed.     

Extended cavity model analysis of stacked microstrip ring antennas

Microstrip ring antennas deserve special attention because they can yield a larger bandwidth compared to other conventional patches and outstanding gain-bandwidth characteristics that renders them useful for applications that require reduced size and good radiation efficiency, like in the area of mobile communications. Stacked microstrip ring antennas for dual-frequency behavior and improved bandwidth are studied and analyzed. The cavity model for single microstrip antennas is extended with some modifications for the stacked geometry to account for the coupling between the upper and lower cavities, fringe fields, dispersion effects, and the effective loss tangent of the dielectric material. Green's functions are used to allow for modal analysis and closed-form solutions. The results for the radiation patterns and input impedance predicted through this simple model are compared with experimental data     

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     

Theoretical and experimental investigations on microstrip active array antennas and power combiners

In this paper, microstrip active array antennas and power combiners are investigated. The mutual impedance of a rectangular microstrip patch array is analyzed based on the Richmond's reaction integral equation and Galerkin technique in spectral-domain. The computer-aided analysis and design of the active array are then carried out by coupling the mutual impedances to the large-signal characteristics of Gunn diodes with a harmonic balance technique. Based on the theoretical study, microstrip active patch array antennas are investigated experimentally.     

An experimental investigation of electrically thick rectangular microstrip antennas

The electromagnetic properties of electrically thick rectangular microstrip antennas were investigated experimentally. Antennas were fabricated with different patch sizes and with electrical thicknesses ranging from 0.03 to 0.23 wavelengths in the dielectric substrate. The resonant frequencies were measured and compared to existing formulas. The bandwidth was calculated as a function of electrical thickness and the antenna radiation patterns were measured.