Low-cost broadband millimetre-wave array antenna using waveguide/microstrip feed network and slot pair

A low-cost broadband millimetre-wave planar 30/spl times/30 array antenna is presented. The antenna is fed by a microstrip feed network in the H-plane to decrease fabrication costs, and a waveguide feed network in the E-plane to reduce the feed line loss. The waveguide and microstrip feed network are coupled through the proposed slot pair. The slots are placed one quarter of a guided-wavelength distance apart, so that the reflected waves from the slots cancel each other. A conductive bar is laid above the slots to increase the coupling, which increases the antenna gain by about 1 dBi. The maximum gain is 30.5 dBi at 41.5 GHz. The measured bandwidth is as broad as 7.1%.     

Corporate feed design for microstrip arrays

A design technique for an embedded microstrip corporate feed is presented. The aim of the design is to shape each corporate feed junction to achieve a tapered and in-phase output current distribution. From this, a Dolph-Chebyshev array sum pattern may be constructed. In the experiments, the designed corporate feed is used to excite a five-element equispaced linear array of overlay microstrip dipoles. It is found both theoretically and experimentally that a 20-dB Dolph-Chebyshev broadside sum pattern can be synthesized in the H-plane at 8.5 GHz. Mutual coupling among the dipoles is included in this analysis. The pattern degradation due to manufacturing tolerances on the alignment between the feed network and the dipole array is discussed     

一种波导裂缝阵列天线设计方法

结合等效电路法和有源导纳法,将设计波导裂缝阵列天线的Elliott方程改写为两个方程组进行求解,利用归一化电导迭代求解两个方程组,得到裂缝参数,避免了直接求解二元非线性方程而产生的大量无用解。互耦系数gmm的计算采用Taylor级数展开式近似。用等效电路法与本文方法分别设计了64元驻波线阵,仿真结果表明,本文方法降到了天线副瓣。     

Coplanar waveguide feed for microstrip patch antennas

A coplanar waveguide (CPW) loop is shown to be an effective low VSWR feed for microstrip antennas. The low VSWR transition between the CPW and the antenna is obtained without the use of a matching circuit, and it is relatively insensitive to the position of the antenna and the feed.<>     

Arbitrarily polarized slot radiators in bifurcated waveguide arrays

The feasibility of obtaining arbitrary polarization in both one- and two-dimensional arrays of slots in dual mode bifurcated Waveguides has been demonstrated. The radiating element consists of a pair of crossed slots in the sidewall of a bifurcated rectangular waveguide that couple to even and odd waveguide modes. One linear polarization is excited by the even or "sum" mode and the orthogonal linear polarization is excited by the odd or "difference" mode. By superposing the sum and difference modes in the proper amplitude and phase, any arbitrary polarization can be realized. A two-dimensional array consisting of eight waveguide linear arrays, ferrite phase shifters for scanning in the plane normal to the linear arrays, and a feed network for power distribution and polarization control was constructed. Good radiation performance for various polarizations was obtained. In the case of linear polarization, the cross polarization component was on the order of -25 dB and in the case of circular polarization, the axial ratio was on the order of 1 dB. The polarization was controlled with a ferrite phase shifter. Close-in sidelobes of better than 20 dB were obtained for all polarizations. The preceding performance characteristics were obtained over a scan range ofpm20degand over a 6 percent frequency band.     

A self-matching wideband feed network for microstrip arrays

A novel technique for feeding microstrip antenna arrays is proposed. It consists of a microstrip feed network designed to operate in dual standing and traveling-wave modes and provide uniform excitation to its elements with either mode. It, therefore, produces a uniform aperture distribution, regardless of the array element input impedances. The traveling wave propagates when radiating elements are matched, but resonant standing wave prevails if loads become mismatched. Since the feed network resonance does not alter the array excitation, it can be used in combination with the radiating patch resonance to broaden the impedance bandwidth. The physical reasons for such behaviors are explained and experimental verification are provided. The generalization of the concept to large arrays is also discussed     

CPW feed circularly polarised microstrip antenna using asymmetric coupling slot

Design of a coplanar waveguide (CPW) feed square microstrip antenna with circular polarisation (CP) radiation is described. This CP design is achieved by using an asymmetric inductively coupling slot in the ground plane of the CPW feed line. Results show that the proposed antenna can have a CP bandwidth of 2.4%, whereas a simple inclined coupling slot case has 1.6% CP bandwidth at a fixed square patch size. Typical experimental results are presented and discussed     

新型带扇形馈源的宽带缝隙天线

介绍了一种新型的采用扇形微带馈源的宽带缝隙天线,给出了反射损失曲线和辐射方向图。该天线采用稍高的相对介电常数（εr=4．3）和薄基片（h=1．1mm）,获得了约106％的阻抗带宽（S11≤-10dB）,频率范围是1．65GHz～5．38GHz。采用电磁仿真软件Ansoft HFSS8．0^TM对几个天线尺寸的影响进行了仿真与讨论,并与文献[6]的结果相比较,验证了设计的有效性,同时也证明了结果的可靠性。     

Characterization of tapered slot antenna feeds and feed arrays

A class of feed antennas and feed antenna arrays used in the focal plane of paraboloid reflectors and exhibiting higher than normal levels of cross-polarized radiation in the diagonal planes is addressed. A model which allows prediction of element gain and aperture efficiency of the feed/reflector system is presented. The predictions are in good agreement with experimental results. Tapered slot antenna (TSA) elements are used as an example of an element of this type. It is shown that TSA arrays used in multibeam systems with small beam spacings are competitive in terms of aperture efficiency with other, more standard types of arrays incorporating waveguide type elements     

小型波导缝隙天线阵的改进设计方法研究

利用传输线理论构造负载阻抗的近似计算公式,采用数值逼近法直接计算阵列中的缝隙归一化导纳,从而可以在Elliott波导缝隙天线阵设计过程中避免使用感应电动势法和矩量法,进而可以提高设计速度.最后采用该方法设计了工作频率为9.375GHz的缝隙阵结构参数,仿真结果表明改进设计方法比较有效.     

A design procedure for slot arrays fed by single-ridge waveguide

R.S. Elliott's (1983) design procedure for arrays of longitudinal slots in one broad wall of each rectangular waveguide is extended to the case in which the waveguides have ridges in the opposite broad walls. External mutual coupling has been taken into account. A two-be-eight array was constructed and tested, and the results validate the theory. Ridging is significant because it permits E-plane scanning from broadside to endfire     

一种抑制波导窄边缝隙阵列天线交叉极化的方法

为了抑制波导窄边缝隙阵列天线交叉极化电平,采用一种在波导外壁开非倾斜缝隙、在波导内壁开倾斜缝隙的方法。利用电磁仿真软件HFSS进行仿真,得到孤立缝隙与阵中单个缝隙的电导函数。设计了一个47单元X波段波导窄边缝隙均匀直线阵列,与常规缝隙阵列相比,天线交叉极化电平降低了6.8 dB。     

Design of slot arrays in waveguide partially filled with dielectric slab

The Elliot procedure for the design of a waveguide slot array is extended to the case of partially filled radiating waveguides. The dielectric slab lies on the top of the radiating waveguide, i.e. on the slotted wall. The proposed solution prevents some of the most common drawbacks of waveguide slot arrays. Results are validated against a commercial FEM software.     

双极化微带缝隙天线单元研究

研究了一种S波段双极化十字缝隙天线单元,利用电磁仿真软件仿真分析了缝隙宽度对驻波和交叉极化性能的影响。仿真结果表明,天线的驻波和方向图特性较好,增大缝宽展宽驻波带宽但没有明显提高天线的交叉极化电平。测试结果与仿真结果基本吻合。     

A twin slot antenna on a layered substrate coupled to a microstrip feed line

A method is described for calculating the input impedance as seen by the detector for a twin slot antenna structure. This technique is then used to analyze several twin slot antenna configurations, leading to improved performance.     

Nonplanar microstrip arrays

Pattern synthesis using planar arrays was done extensively in the past, mainly in the context of radar antennas where a cosec² beam is required in the elevation plane. The synthesis leads to a set of coefficients for the array elements which may be difficult to realize and which, if realizable, may lead to a very narrow-band performance. In this paper, a new type of array is proposed. The shaped-beam nonplanar array is an array of microstrip elements, where the phasing is not generated through the feeding network, but by shaping the substrate. Microstrip arrays lend themselves well to a configuration similar to the one proposed, and as it is shown, the final thickness of the array does not exceed a few substrate thicknesses     

Integrated waveguide slot antennas

Waveguide slot antennas integrated on microwave laminate are presented, and single and dual slot antennas are described, which operate at 10 GHz.     

Investigation of wide-band microstrip slot antenna

This paper presents the simulation and experimental investigations of a printed microstrip slot antenna. It is a quarter wavelength monopole slot cut in the finite ground plane edge, and fed electromagnetically by a microstrip transmission line. It provides a wide impedance bandwidth adjustable by variation of its parameters, such as the relative permittivity and thickness of the substrate, width, and location of the slot in the ground plane, and feed and ground plane dimensions. The ground plane is small, 50 mm/spl times/80 mm, and is about the size of a typical PC wireless card. At the center frequency of 3.00 GHz, its width of 50 mm is about /spl lambda//2 and influences the slot impedance and bandwidth significantly. An impedance bandwidth (S/sub 11/=-10 dB) of up to about 60% is achieved by individually optimizing its parameters. The simulation results are confirmed experimentally. A dual complementary slot antenna configuration is also investigated for the polarization diversity.     

A study on wideband gap-coupled microstrip antenna arrays

A method for increasing the bandwidth of microstrip antenna arrays by using gap-coupled patches is described. The input impedance properties of gap-coupled patches are analyzed by the use of the spectral dyadic Green's function for a grounded dielectric slab and the moment method. The dependence of different parameters such as s, L and ϵr on the impedance characteristics is investigated. In considering the effect of feed network, the impedance bandwidth for a VSWR<2 of two-element gap-coupled patch array is as large as 2.5 times that of an ordinary array. The radiation patterns over this bandwidth are measured and discussed. All the microstrip antenna arrays are fabricated on a substrate with ϵr=2.86, h=1.5 mm. A comparison of theoretical and experimental results for both input impedance and radiation patterns are given     

Analysis of a slot microstrip antenna

The slot microstrip antenna is used as a folded slot dipole symmetrically fed across a gap by means of a strip line. A theoretical model equivalent to several lossy transmission lines had been described previously to explain the bandwidth and the radiation admittance. The theory is improved when coupling between the two equivalent radiating lines of every slot is taken into account, and explains a fourth resonance near the third one, which had been measured on several models. Theoretical results and experiments are in good agreement. They are radiation admittance in a wide frequency band, current distribution along each slot and radiation patterns.