Full-wave spectral-domain analysis of coplanar strips

A dynamic analysis of coplanar strips (CPs) is presented. A spectral-domain stationary expression for the propagation constant has been derived making use of proven concepts of electromagnetic theory (e.g. the reaction concept). For the strip surface current distribution, which is the trial quantity in the stationary expression, a suitable approximation is used. The numerical results, obtained in a straightforward and efficient way, are in excellent agreement with results arrived at by means of more complex methods. The characteristic impedance of CPSs has been determined on the basis of two commonly used definitions. The numerical results show a novel aspect of the dynamic behavior of the impedance (power-related definition) in the upper frequency region     

Optically fed aperture-coupled microstrip patch antennas

Several techniques are presented for feeding microstrip antennas with RF-modulated lightwave signals via an optical fiber. Lightwave-to-RF conversion is performed in a module containing a photodiode, RF circuitry, and a microstrip antenna element. Three different transmitting configurations at microwave frequencies were designed and tested: passive matching, matching with amplification, and an injection-locked oscillator. In each case, the only connections to the antenna modules were an optical fiber and DC bias lines     

Full-wave analysis of coplanar strips considering the finite stripmetallization thickness

An extensive analysis, based on a full-wave mode-matching technique, is described for coplanar strips (CPS) incorporating the strips' finite metallization thickness. Results for the effective dielectric constant and characteristic impedance are presented to show the effect of the metallization thickness. It is found that the characteristic impedance has a strong dependence on the metallization thickness, which signifies the fact that the finite metallization thickness needs to be considered in designing practical microwave circuits employing CPS. Numerical results of CPS with zero metallization thickness obtained using this method are found to be in good agreement with those published previously. Extensive investigation of the numerical convergence of these results is also described     

Full-wave analysis of aperture-coupled microstrip lines

Two methods are presented for the analysis of aperture-coupled microstrip lines. Assuming a quasi-transverse electromagnetic traveling wave incident on the feeding line, an expression for the wave on the coupled line is derived. First, the moment method is used and the current on the coupled line is represented by a traveling wave propagating away from the slot. In the second method, the reciprocity theorem is applied to the coupled line. Both the moment method and the reciprocity method make use of the exact Green functions and produce results that are in very close agreement. An equivalent circuit is derived and the S-parameters are computed. Theoretical results are verified with measurements     

Stacked patch antenna fed by a coplanar waveguide

A broadband patch antenna fed by a coplanar waveguide (CPW) is presented. The antenna was designed based on the stacked patch technique developed for aperture-coupled patch antennas. It is similar in configuration to a conventional stacked patch antenna, but the lower of its two patches is fed with a conductor-backed CPW Both simulation and measurement show that the antenna has bandwidth of over 10% (for |S/sub 11/| /spl les/ -10 dB) centred at 10 GHz.     

Grounded coplanar waveguide-fed aperture-coupled cavity-backedmicrostrip antenna

Microstrip antennas aperture coupled to a grounded coplanar waveguide (GCPW) have been fabricated on a single layer substrate and studied experimentally and theoretically. Through-plated via holes are used to suppress spurious parallel plate modes. Measurements demonstrate that this antenna element has good performance for both bandwidth and radiation patterns. Calculations using a commercial CAD package are in reasonable agreement with measured data     

Full-wave analysis of multilayer coplanar lines

A full-wave analysis of a coplanar waveguiding structure with multiple dielectric layers is presented. The results of a hybrid approach that combines the finite-element method and the conformal-mapping technique are compared with those of the spectral-domain approach. Numerical results for effective dielectric constants, characteristic impedances, current distributions, and field distributions for various multilayer coplanar line structures are presented and discussed. The computed results are compared with the available quasi-static ones     

Analysis and design of aperture-coupled microstrip patch antennasand arrays fed by dielectric image line

This paper presents the analysis and design of aperture-coupled microstrip patch antennas and arrays fed by an dielectric image line. A theory based on the cavity model of the microstrip patch antenna and the change in the modal voltage of the image line at the aperture was developed to analyze the single element aperture-coupled microstrip patch antenna. The theory developed was combined with the array theory to design linear traveling wave arrays at X-band and Ka-band frequencies. The required taper in the excitations of the individual patches of the array was achieved by varying the aperture dimensions. Experiments show very good results for the antennas and the arrays     

Active millimetre-wave aperture-coupled microstrip patch antennaarray

An active millimetre-wave aperture-coupled microstrip patch and four element array are presented. The design methodology is discussed and experimental measurements between 41 and 42 GHz are presented. The results presented should have useful applications in phased arrays and communication systems at EHF frequencies     

Full-wave aperture coupled patch antenna

An aperture coupled patch antenna with a dual-lobed (cavity mode TM/sub 200/) radiation pattern is described. The antenna employs a full-wavelength long patch fed via a butterfly-shaped aperture and a stripline feed network. This configuration provides high patch to feed network coupling and reduced back radiation. Measured return loss and pattern data are presented with proposals for several potential applications of this element.<>     

一种改进的圆极化三角形口径耦合贴片天线

提出并设计了一种改进的宽带圆极化三角形口径耦合微带贴片天线。该天线由L形微带线、三角形缝隙和三角形贴片组成。通过L形微带线形成圆极化,三角形缝隙和三角形贴片形成单向辐射,缝隙和贴片印刷在不同的介质基片上以提高天线增益并缩减口径尺寸,同时在三角形贴片上切去一个角改善天线的圆极化特性。用HFSS设计了一款L波段的口径耦合贴片天线。仿真结果表明,天线的阻抗带宽26.5%,圆极化带宽22.5%,平均增益7.7 d B。     

Full-wave modeling of coplanar waveguide discontinuities withfinite conductor thickness

An extended version of the spectral domain approach (SDA) is developed to analyze discontinuities in open coplanar waveguide with finite metallization thickness. By making use of the exact Green's function in the spectral domain, the effects of surface wave and radiation phenomena are accurately accounted for. Both longitudinal and transverse components of the aperture electric fields are used in the analysis to allow modelling of structures with large transverse dimensions at high frequencies. The procedure also includes mode conversion near the discontinuities. As an illustration of the method, analytical steps and computed scattering parameters of the coplanar waveguide short-circuits and transitions are provided and compared against measured data     

Full-wave analysis of coplanar waveguides by variational conformalmapping technique

A new full-wave analysis of coplanar waveguides is presented. The modified mapping technique of C.P. Wen (1969) is used to map the original infinite domain into a finite image domain and also to account for the singularity of fields near the conductor edges. The finite thickness of the dielectric substrate is considered together with the assumptions of lossless guides and negligible metallization thickness. The current distributions on the center signal strip as well as the tangential electric fields over the slot along the air-dielectric interface are examined. Numerical results for the frequency-dependent effective dielectric constants and characteristic impedances of coplanar waveguides are presented. Particular attention is given to the electric field distributions over the air-dielectric interface of slots and the current distributions of the signal strip     

一种天线馈源用宽带孔径耦合层叠微带贴片阵的设计

介绍了一种宽带孔径耦合层叠微带辐射单元的工作原理,着重分析了该辐射单元主要结构尺寸对其阻抗带宽的影响。该辐射单元阻抗带宽（VSWR≤2：1）在S波段达到了30％以上。作为某抛物反射面天线的馈源,由4个该辐射单元组成四单元微带贴片天线阵后,其性能满足天线系统要求。     

Broadband dual-polarized aperture-coupled patch antennas withmodified H-shaped coupling slots

This paper presents a new design of aperture-coupled patch antennas with modified H-shaped coupling slots for achieving dual-polarization radiation with high isolation over a wide bandwidth. By using the proposed coupling slots, whose two upper side arms are bent inward with a proper angle, the isolation between the two feeding ports of the patch antenna can. greatly be improved, compared to the case with conventional H-shaped coupling slots. Also, when using a pair of modified H-shaped coupling slots for each feeding port, the isolation can further be improved; a high degree of isolation (< -34 dB) over the entire impedance bandwidth greater than 15% and good cross-polarization level (> 20 dB) for the two polarizations can be achieved. Details of the proposed design and experimental results are presented and discussed     

Tunable coplanar patch antenna using varactor

The operating frequency of a coplanar patch antenna is tuned using a varactor mounted at one of the radiating edges. The coplanar patch antenna is tunable from 4.92 GHz at 0 V to 5.40 GHz at 19.5 V with a return loss better than 14 dB in this frequency range. The antenna provides a return loss better than 32 dB in the tunable frequency range of 5.16 to 5.40 GHz.     

Slot-array antennas fed by coplanar waveguide for millimeter-waveradiation

Slot-array antennas with parasitic slots, slot-array antennas fed by coplanar waveguide (CPW), and two-dimensional slot-array antennas fed by CPW were fabricated on fused quartz substrates, and the receiving properties of the antennas were investigated at 94 GHz with the goal of increasing the power gain of the slot antennas. It was found that the power gain of the slot antenna could be increased by 11 dB over a single-slot antenna by using a two-dimensional (8×3) slot-array antenna fed by CPW. It was confirmed that the improvement of the power gain was caused by decreasing surface-wave power in the substrate and by sharpening antenna patterns perpendicular to the substrate     

无表面波损耗的孔耦合贴片天线的设计

设计了一种新结构的孔耦合贴片天线。该天线结构将贴片连用制作贴片的介质基板一起放置在一个矩形金属框里，彻底阻断了表面波的传输，该天线结构的尺寸比一般贴片天线要小很多。但却具有更高的增益，还介绍了对该天线结构的数值模拟。样品制作和实验测量，测量数据显示矩形金属框使天线的增益在9GHz到11GHz的频率范围内平均提高了0.7dB，该天线的工作频带超过了20%，带内平均增益为8.3dBi，同时天线具有良好的辐射方向图。     

Twin Vivaldi antenna fed by coplanar waveguide

The authors describe twin Vivaldi antennas directly fed by a coplanar waveguide. They have been designed and measured for various angles between the radiating slots. All the designs show a centred zero in the E plane with a low cross-polarisation. In the H plane they provide zeros for φ=90° and 270° and are omnidirectional for other values     

Circularly polarised printed antenna fed by coplanar waveguide

A new structure of the circularly polarised printed antenna fed by coplanar waveguide (CPW) is proposed. FDTD analysis predicts the radiation of the circularly polarised wave from the antenna. The validity of this analysis is established by comparing with experimental results