基片集成非辐射介质波导激励电路研究

随着直接在印刷电路板(PCB)或金属化的介质板上制作基片集成非辐射介质(SINRD)波导的概念提出,如何用平面电路的方式激励此种SINRD波导是今后广泛应用SINRD波导电路的要解决的关键技术之一,这是因为这一技术的解决可以为平面多层化毫米波系统在更高频率上的使用打下基础.本文提出了一种利用微带线到槽线过渡结构,然后利用槽线准TEM波主模和SINRD波导LSM11主模的场型相似性,用槽线去激励PCB型SINRD波导的新型馈电结构.通过使用多层结构,电路由两层的ArlonTC600的PCB组成,从微带结构到槽线的过渡电路可以直接焊接在稍薄的板子上.接下来可在接近SINRD波导介质条带的中心位置激励所需的工作模式LSM11模,这种槽线到SINRD波导的配置可以获得更宽的带宽和高度的集成.仿真和实验结果证实了上述观点的正确性.     

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 and measurement of NRD-guide leaky wave coupler in Ka-band

A new structure for a nonradiative dielectric (NRD) waveguide directional coupler has been developed. The structure combines two NRD guides and a dielectric slab guide in order to utilize a leakage mechanism for coupling. The coupling depends on this leaky mechanism, but not on field interactions as in a conventional proximity coupler. A theoretical formula for calculation of the decay constant is derived. The field along the NRD guide and the decay constant are measured at Ka band (35 GHz) and compared with the theoretical data. Reasonable agreement between the measured and theoretical data is found     

Full-wave nonlinear analysis of nonradiative dielectric guide circuits including lumped elements

This paper describes the full-wave numerical analysis of complex nonradiative dielectric (NRD) guide structures including linear or nonlinear lumped elements. The numerical results described in this paper, validated through experimentation, show that the method is suitable for NRD guide and similar circuits. Nonlinear analysis of a single-ended NRD guide mixer is carried out, and the results are experimentally verified. Nonlinear harmonic-balance analysis of a novel leaky-wave balanced mixer circuit with very good tolerance of manufacturing inaccuracies in NRD guide configuration in Ka-band is then carried out. Due to curved segments, and orders of magnitude difference in the dimensions of different parts, the analysis of this component requires certain simplifying assumptions. How these can be implemented without sacrificing much accuracy is described. Until now, the design of NRD guide components, especially those using nonlinear effects, has been mostly trial-and-error-based. Here we demonstrate that a more systematic approach is possible.     

Coupling and quality factors in parallelepiped nonradiative dielectric resonators

In this work, the quality factors and the coupling effects have been investigated for parallelepiped dielectric resonators in nonradiative dielectric (NRD) waveguide, in order to achieve fundamental information for the design of various types of advanced filters. The unloaded quality factor has been calculated taking into account both conductor and dielectric losses through a straightforward version of the perturbation method. The electromagnetic coupling as a function of the distance between NRD guide and resonators has been evaluated through proper extensions of typical lumped equivalent circuits, thus quantifying resonance frequency shifts, external and loaded quality factors, etc.. To validate the derived theoretical models, suitable measurements of all these parameters have been performed at microwaves on X-band NRD prototypes.     

Leaky wave antenna based on image NRD guide with staircase-shapeddielectric slab

A leaky wave antenna based on the use of an asymmetric image nonradiative dielectric (NRD) guide has been studied experimentally. By using a staircase-shaped image NRD guide, the gain bandwidth of the antenna becomes three times that of a leaky wave antenna using an ordinary image NRD guide. Moreover, this antenna employs a flared horn in the NRD guide which makes the H-plane beamwidth controllable     

Design and fabrication of a nonradiative dielectric waveguidecirculator

A technique is described for constructing a high-performance nonradiative dielectric waveguide (NRD guide) circulator for use at 50 GHz. A mode suppressor, which serves to reduce unwanted modes to a negligible level, was devised and used to improve circulator performance significantly. A half-wavelength step transformer was installed at each port of the circulator to increase the operational bandwidth. The insertion loss of this circulator is less than 0.3 dB, and the 20-dB isolation bandwidth is about 2.6 GHz. Characteristics of the NRD guide circulator are analyzed based on an equivalent circuit representation. This analysis considerably facilitates the design procedure of the circulator     

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。     

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.     

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.     

Leaky NRD guide fed microwave planar antenna

A novel and unique application of leaky waveguides as feeding systems for microwave planar antennas is presented. A new leaky nonradiative dielectric (NRD) guide based on a grating structure is proposed, and a planar array slot antenna using this leaky waveguide is constructed and measured at 23 GHz.<>     

New NRD guide MM wave oscillators

A new millimenter-wave Gunn oscillator is described. The present structure makes use of NRD guide and metal resonant cap. The field expressions and the design considerations of NRD guide are discussed. Some experimental results of 8mm and 6mm band oscillators show that the new Gunn oscillator has a future as an integrated millimeter-wave source.     

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     

Dielectric rod antenna based on image NRD guide coupled to rectangular waveguide

A dielectric rod antenna based on an image NRD guide fed by a slot in the broad wall of a rectangular waveguide is proposed. This configuration is developed for the use in the design of an array of this antenna. The antenna characteristics are investigated using the finite difference time domain (FDTD) technique. Measured results at 30 GHz band are presented to validate the numerical analysis.     

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.     

Numerical and experimental analysis of nonradiative dielectric guide modulator and mixer at Ka band

This letter describes the numerical analysis of an on/off modulator and a single-ended mixer in nonradiative dielectric (NRD) guide configuration at Ka band. Currently, only experimental results are available for such structures. A shunt mounted diode switch in NRD guide configuration is analyzed using the finite element method (FEM) in conjunction with linear circuit simulation. A novel mixer is similarly analyzed using FEM and harmonic balance analysis. The results obtained from numerical analysis are compared with measured results. It is demonstrated that some counter-intuitive experimental results can be explained through numerical analysis.     

Hybrid integration technology of planar circuits and NRD-guide forcost-effective microwave and millimeter-wave applications

An architecture called the hybrid planar/non-radiative-dielectric (NRD) waveguide integrated technology is proposed as a building block for constructing microwave and millimeter-wave circuits. This hybrid approach of integration offers a unique possibility of exploiting inherent complementary advantages of planar structures and NRD waveguides for low-cost wireless applications while eliminating the potential drawbacks associated with both dissimilar structures. Compared to the existing NRD-guide related technology, the proposed framework consists of relocated planar structures on the top and/or the bottom plates of an NRD-guide, sharing the common ground planes. Such a hybrid scheme is particularly suitable for millimeter-wave systems in which active devices can be made with the planar-line technique while passive components can be made with the NRD-guide technique. The two subsets of a complete functional system are interconnected through a class of aperture-based transitions which can be designed to have wide-band performance. In addition, the multichip module (MCM) technique is readily achieved under this proposed scheme. Experimental prototypes, including passive-component and active-device, based on the new hybrid technology presented in this paper, show that the novel hybrid technology promises to be useful in the design of future microwave and millimeter-wave circuits and systems     

新型NRD波导漏波天线特性分析

本文利用多模网络理论结合模匹配技术对任意横截面NRD波导漏波天线的辐射特性作了系统的分析,这些天线可以作为低成本的实用天线应用在毫米波系统中.文中着重研究了结构参数的变化对天线辐射特性的影响.这些计算结果对这类新型漏波天线的设计和确定NRD波导作为传输结构时的制作容差有重要的指导意义.     

Aperture coupled microstrip patch antenna fed by nonradiating dielectric waveguide

Owing to its low loss property at millimetre-wave frequencies, the nonradiating dielectric (NRD) waveguide is very attractive for use as a feed network in planar arrays. The design, fabrication and testing of a microstrip patch antenna fed by NRD guide at X-band is described. Radiation patterns are measured and presented.<>     

An analytical method for direct calculation of E and H-fieldpatterns of conductor-backed coplanar waveguides

A new direct method of computing the electromagnetic field patterns surrounding the conductor-backed coplanar waveguide (CPW) structure is proposed. Analytical closed-form expressions describing the quasi-TEM field pattern in both the air and the dielectric substrate for conductor-backed CPW's are presented. This approach is based on a new technique which employs a series of inverse conformal mappings to transform a known field pattern from a rectangular structure back into the CPW structure in order to obtain its unknown field pattern directly. A computer program based on this method has demonstrated the speed at which the fields can be plotted compared to existing methods which require repetitive application. Graphical results of these field patterns are presented as a function of the CPW's geometry and dielectric substrate thickness. These held maps which have been directly drawn with true curvilinear squares enable the determination of power flow density, since the same power flows through each square. This direct method of characterizing the power flow density throughout the CPW structure could become an important design tool for the modeling of coplanar monolithic microwave integrated circuits (CMMIC's)