A generalized surface-volume integral-equation (SVIE) approach for analysis of hybrid planar/NRD-guide integrated circuits

A generalized surface-volume integral-equation approach (SVIE) has been proposed and developed for accurate modeling and analysis of hybrid planar/nonradiating dielectric (NRD)-guide integrated circuits. On the basis of vertical modes in basis functions for NRD-guide circuits, vertical integration in space-domain is carried out analytically and a set of first-order Green's functions is constructed. Then, the solution of the volume integral-equation concerning with the NRD-guide circuits has been reduced to a two-dimensional planar problem in connection with each vertical mode. In this way, only the diagonal submatrices need to be calculated due to the orthogonal property of different vertical modes. A reduced calculation region technique is used for handling higher order vertical modes in which the fields are confined in the slot areas and their vicinities. The method was applied to a class of different hybrid structures. The results are in good agreement with measured results or the results obtained with other methods.     

Substrate integrated nonradiative dielectric waveguide

A new substrate integrated circuits (SICs) fabrication technique is proposed for realizing nonradiative dielectric (NRD) waveguide circuits. This new technique called substrate integrated NRD (SINRD) guide allows the NRD guide be integrated within a dielectric substrate by drilling a pattern of air holes. Dispersion analysis and design considerations of the new structure are discussed. A hybrid integrated scheme of planar and SINRD circuits is demonstrated for the first time with simulation and measurement results.     

Theoretical and experimental research on nonradiative dielectric waveguide directional couplers

A practical design of nonradiative dielectric (NRD) waveguide directional couplers is presented. The dispersion characteristics of coupled NRD-guides and the scattering coefficients of NRD-guide directional couplers are studied as well as the transitions from metal rectangular wave-guide to NRD-guide couplers. Experiments of 3-dB and 10-dB NRD-guide couplers in ka-band show that the couplers are of good performance and promise in millimeter-wave integrated circuits.     

Complete characterization of transmission losses in generalizednonradiative dielectric (NRD) waveguide

In this paper, transmission losses of the generalized nonradiative dielectric (NRD) waveguide are modeled and presented by our closed-form equations for the design of hybrid and monolithic millimeter-wave integrated circuits. This generalized structure includes our recently proposed channelized NRD-guide. Parametric effects are studied with respect to complex propagation constant and characteristic impedance, and some useful guidelines are generated for practical design considerations. Calculated results are discussed separately for the conductor and dielectric losses for the two fundamental longitudinal section electric (LSE) and longitudinal section magnetic (LSM) modes. It is found that the LSE mode may have losses, in some cases, comparable or even smaller than those of its LSM counterpart, contradicting what has usually been perceived for the conventional NRD-guide design     

Hybrid planar NRD-guide magic-tee junction

A new magic-tee circuit is proposed and developed, which is based on the hybrid integration technology of a planar and nonradiative dielectric (NRD) guide. The magic-tee junction combines an NRD-guide T-junction with a microstrip T-junction. Furthermore, LSM/sub 10/-mode radiators are introduced in the magic-tee circuit to reduce its resonance problem. Measured results show that an isolation of 20 dB can easily be achieved between the sum and difference ports.     

Analysis and Design of Bridged NRD-Guide Coupler for Millimeter-Wave Applications

A new nonradiative-dielectric (NRD)-guide directional coupler using two NRD waveguides interconnected with a bridge is proposed and demonstrated. Propagation constants of the bridged NRD-guide couplers are investigated with an electric-field integral-equation method, and modeling results show that there is a maximum of coupling coefficient when the thickness of the bridge is made around 0.68 of the plate separation. In this case, the coupling length is reduced approximately 60% and the bandwidth under the tolerance limits of$pm$0.5 dB of deviation for 3-dB coupling is nearly doubled with reference to its conventional counterparts. The use of a bridge not only improves the mechanical stability, but also makes the coupler performance reproducible. Experimental prototypes are fabricated with two 90$^circ$elbow bends that are used for the arms and the bridge-connected coupler section is terminated at both ends by tapered half-circle sections. A calibration procedure is used to remove mismatch effects between the NRD-guide and the rectangular waveguide in the measured results. Advantages of the new coupler as a passive component are shown for millimeter-wave integrated circuits.     

Computer-aided design and optimization of NRD-guide modesuppressors

A novel class of optimized nonradiative dielectric waveguide (NRD-guide) mode suppressors are proposed for wideband applications in passive and active NRD integrated circuits. A rigorous field-theoretical analysis is made by using the frequency-domain TLM technique. The optimum design is based on a filter-like scheme with a low-pass filter simulation technique and its performance-prediction algorithm. Compared to the existing choke metallic pattern, the proposed mode suppressor demonstrates excellent capabilities of effectively suppressing unwanted modes while offering a more compact geometry. Using the geometry proposed in this work for a three-section low-pass filter, for example, it is found that the transmission loss of the mode suppressor is better than -30 dB over the frequency band of interest which is well confirmed theoretically and experimentally. In addition, the length of the resulting mode suppressor becomes shorter than its counterpart using the choke metallic pattern by 20%. The theoretical prediction of electrical performance is well confirmed by our measurements     

Insulated Nonradiative Dielectric Waveguide for Millimeter-Wave Integrated Circuits

An improved version of the nonradiative dielectric waveguide (NRD-guide), called an insulated nonradiative dielectric waveguide, is proposed for millimeter-wave integrated circuits. This dielectric waveguide can overcome some difficulties which arise when high dielectric material is used in the NRD-guide. Guide wavelengths and transmission losses were measured at 50 GHz and compared with theory. In addition, some basic circuit components such as bends, ring resonators, chip resonators, and T-junctions were fabricated on the basis of the insulated NRD-guide and tested to confirm their usefullness in millimeter-wave integrated circuits. The fabricated components operated as expected without suffering from any appreciable radiation at curved sections and discontinuities.     

Design technique and performance assessment of new multiportmultihole power divider suitable for M(H)MICs

Novel power-dividing structures are studied for application in solid-state power amplifiers and array-antenna related beam-forming networks. This paper is directed to the design and study of a class of compact sinusoidally tapered power dividers suitable for use in monolithic and hybrid microwave integrated circuits at microwave and millimeter-wave frequencies. An efficient computer-aided design (CAD) technique is used in the accurate design of such planar circuits generally having irregular topologies and contours. A so-called multiport and multihole power divider is developed and modeled and a 1-9 power divider is designed through a cascading of four sets of 1-3 simple multihole dividers. Compared to conventional structures, advantageous features of the new power divider are demonstrated such as small size, short linearly aligned ports, potential high-power handling capability, potential large bandwidth, and easy post-fabrication tuning. Capacity of the proposed CAD technique is shown in the design of an electrically large multiport power dividing circuit for which only limited computer resource and time are required. Electrical performance and design effectiveness of the new multiport and multihole divider are assessed with design prediction and experimental results for Ku-band prototypes     

New multilayer planar transmission lines for microwave andmillimeter-wave integrated circuits

New types of planar transmission lines employing multilayer structures are proposed for possible applications in microwave and millimeter-wave integrated circuits. Detailed investigations are presented through numerical results calculated using the spectral domain technique. The newly proposed transmission lines have many attractive features such as a large impedance range, flexibility and ability to realize complicated, densely packed integrated circuits, as well as miniaturization through the use of thin dielectric layers. Additionally, they possess all of the inherent advantages of the CPW and microstrip line. Their use in microwave circuits is exemplified through a low-pass filter realized using the new slot-coplanar lines with less than 0.5-dB insertion loss and better than 20-dB return loss. The filter's measured and calculated performances also agree well     

NRD波导槽缝激励的严格分析

NRD波导的激励是平面／非平面微波混合集成电路的一个关键问题．文中采用并矢格林函数结合矩量法严格分析了通过横向缝隙有效激励NRD波导LSE01模的方法．该方法具有结构简单、体积小、耦合效率高、泄漏能量小等优点,对混合微波集成电路的设计具有重要的实际意义。     

间隙波导技术及其空间应用

间隙波导(GW)是一种基于非接触电磁带隙(EBG)结构的新型人工电磁(EM)材料，其独特的非接触结构和宽带电磁屏蔽特性在构建新型电磁传输线及屏蔽结构方面显示出极大的优势和灵活性，为微波毫米波部件、电路及天线等领域带来了新的研究视角和实现途径，近年来引起了广泛关注。该文首先简要介绍了间隙波导概念和原理，分析了其技术优势；进一步，根据不同的研究及应用领域分类，全方位地归纳总结了间隙波导技术相关的国内外研究进展情况；最后，结合空间技术背景和发展需求，探讨了间隙波导在空间微波毫米波技术中的应用前景，提出了基于间隙波导技术的非接触式无源互调干扰控制方法及堆叠集成毫米波电路系统两个重要的应用方向。该文工作可为间隙波导技术相关研究和应用提供一定的借鉴与参考。     

Efficient analysis of microstrip-coupled nonradiative dielectric(NRD) resonators for hybrid integrated circuits

Nonradiative dielectric (NRD) resonators have been recently known as excellent stabilizing components for the design of a new class of oscillators based on hybrid integration of planar circuits and NRD-guides. However, an accurate characterization of such a component is needed in order to develop efficient computer-aided-design programs. In this paper, a hybrid planar integrated circuit comprising an NRD resonator is accurately modeled and is coupled to input and output planar microstrip circuits by means of long slots located on the top ground plane of the NRD structure. A reciprocity approach is used to solve the coupling problem between the resonator and microstrip lines. A modal expansion of the field equations has been applied to the NRD resonator in obtaining its rigorous field expressions. Finally, a transmission-line analysis is proposed for the structure, and scattering parameters have been calculated for different slot positions. Results are discussed for various parametric effects on coupling and Q-factor characteristics     

Analysis of inhomogeneously dielectric filled cavities coupled to dielectric-loaded waveguides: application to the study of NRD-guide components

In this paper, we present two contributions. First, we develop a computationally efficient technique for the full-wave characterization of inhomogeneously dielectric-filled cavities connected to inhomogeneously dielectric-loaded waveguides. This method is based on the expansion of the electromagnetic field within the cavity in terms of their solenoidal and irrotational modes. The presented formulation allows the treatment of hybrid modes in the waveguide ports, where the definition of a characteristic modal impedance or admittance is not possible. The multimode scattering matrix of the structure is computed throughout an efficient implementation of the orthonormal-basis method for the calculation of the cavity modes. Secondly, we have employed the present technique for the analysis and design of nonradiative dielectric (NRD) guide components and discontinuities. Moreover, the application of the bi-orthonormal-basis method for the calculation of the full-spectrum of NRD guides is demonstrated as being a very efficient approach for the rigorous treatment of such guides. Next, an efficient computer-aided design tool has been developed for the analysis of complex NRD-guide circuits. We have compared our simulations with theoretical and experimental results available in the technical literature, fully validating our software. This code has been employed for the specific analysis of a linear continuous taper to match two NRD guides with different widths, demonstrating a considerable reduction of the return losses over a wide frequency band. Finally, stopband and bandpass NRD-guide filters based on an electromagnetic-bandgap concept are presented.     

用于杂波抑制滤波器优化设计的混合遗传算法 及其收敛性分析

参差时变动目标显示(MTI)滤波器是在强运动杂波背景下检测弱目标和缓解盲速问题的一种有效方法.选择适当参差码使参差时变MTI滤波器的第一零点尽可能浅,可在有效抑制杂波的同时避免陷入其中的弱目标丢失.本文采用了结合梯度的混合遗传算法(HGA)选择最优参差码,与标准遗传算法(SGA)相比,该算法只需要很小的种群规模.采用马尔可夫链方法证明了HGA是以概率1收敛的全局随机搜索算法.将该算法应用于米波雷达中,性能分析和仿真实验表明,基于混合遗传算法的杂波抑制滤波器设计是可行和有效的.     

Recent development in NRD-guide technology

Recent achievements in the field of the NRD-guide integrated circuits and antennas are reviewed. The main emphasis is placed on a new class of planar antennas which employ a leaky NRD-guide as the feed medium and can be contained in a common housing together with the NRD-guide integrated circuits.     

Analytical and experimental investigations of aperture coupledunidirectional dielectric radiator arrays (UDRA)

Experimental and analytical investigations of unidirectional dielectric radiator arrays (UDRA) are presented for the first time. Attractive electrical performance due to the use of nonradiating dielectric waveguide (NRD) structures is demonstrated. A numerical model based on a cavity-resonator approximation is developed for prediction of radiation properties of the UDRA's. Good agreement between measurements and calculations shows the validity of the modeling approach. On the other hand, the feed technique for the UDRA by microstrip line and coupling-aperture is experimentally investigated. Measurement results show high coupling and radiation efficiencies of the proposed excitation method. Such a circuit configuration allows the combination of planar millimeter-wave M(H)MICs and NRD components in one system for the best use of different technologies     

Characteristic impedance of nonradiative dielectric waveguide and its application

In this paper a formula for determining the characteristic impedance of the nonradiative dielectric waveguide (NRD-guide) is presented. The numerical results are obtained, which are very useful for designing NRD waveguide components, such as impedance transformers, filters, branch-line hybrids, and active circuits. As a practical example for applying the formula, a 3 dB brainched NRD-guide directional coupler was designed and fabricated. The experiments show good consistency with the theory.     

基于BGA互联的毫米波模块三维集成设计

设计了一种利用微波基板作为转接板的毫米波系统级封装（System in Package,SIP）模块。采用球栅阵列(Ball Grid Array,BGA)作为射频信号层间垂直互联传输和隔离结构,实现了三维集成毫米波模块的低损耗垂直传输。对样件测试结果显示,在28~31 GHz频率范围之间,其端口驻波小于1.5,增益大于30 dB。该三维集成结构简单,射频传输性能良好,其体积仅为传统二维平面封装结构的20%,实现了模块的小型化,可广泛用于微波和毫米波电路与系统。     

微波毫米波平面共口径天线北大核心CSCD

随着无线通讯和雷达成像等现代无线系统的迅速发展和广泛应用,人们对系统前端的天线提出了更多的需求。共口径天线将多种不同频带或不同功能的天线集成在同一口径,通过在有限口径内对天线单元进行合理布局,显著提高空间利用效率,并在不同天线之间实现高隔离,确保各天线独立工作。根据辐射口径分布情况,共口径天线设计方法可以分为:嵌套技术、交错技术和复用技术。与立体型共口径天线相比,平面共口径天线具有尺寸小、重量轻、成本低、易于集成等优点。本文介绍了微波毫米波平面共口径天线的研究现状,重点介绍了基于交错技术和复用技术的毫米波平面共口径天线,并对共口径天线技术的发展进行了展望。