Corporate feed in nonradiative dielectric waveguide

The development of a corporate feed for application to antennas fed from a nonradiative dielectric (NRD) waveguide is described. A feed was constructed and tested, and its performance evaluated by allowing the unterminated circuit to radiate as an antenna     

A leaky-wave antenna in nonradiative dielectric waveguide

A leaky-wave mechanism in a nonradiative dielectric (NRD) waveguide is described. The antenna used in the analysis consists of a long slot in one ground plane of the NRD guide; the currents present in the side walls cause the slot to radiate as a traveling-wave antenna. The antenna was designed to operate at 9.5 GHz to reduce the costs involved in working at high frequencies. The analysis of the slot follows the procedure outlined by L.O. Goldstone and A.A. Oliner (1959). A simple expression for the amount of coupling from the guide is derived under certain assumption made because information on the reactances necessary to model the slot is not as yet available. The theoretical coupling values verified by measurement and the design, construction, and performance of both leaky-wave antennas are described     

Integrated travelling-wave antenna for nonradiative dielectric waveguide

A travelling-wave antenna for integrated use in nonradiative dielectric waveguide is described. The antenna is constructed by cutting a longitudinal slot in the waveguide side wall. Results are presented showing the comparison between measured and calculated data.     

An array of coupled nonradiative dielectric waveguide radiators

A novel antenna array that radiates a single mode of multiple coupled nonradiative dielectric (NRD) waveguides, is described. The array is fed by a single NRD waveguide, which is designed to propagate a wave with the same wave number as that of free-space. The individual radiators of the array are spaced at one free-space wavelength, but due to the narrow beamwidth of the individual radiators, grating lobes are effectively suppressed. An eight-element array is described and measurements presented, but the design method can be extended to any number of elements     

Gunn diode oscillator constructed in nonradiative dielectric waveguide

The physical construction of a Gunn diode oscillator in non-radiative dielectric waveguide is described. A stripline construction is used for biasing, and the diode is mounted so as to feed a slot which in turn launches the wave into the wave-guide.     

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.     

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.     

The development of nonradiative dielectric waveguide transmitting front-end in Ka-band

The operating theory,design method and experimental results of the nonradiative dielectric waveguide (NRD-guide) transmitting front-end in millimeter wave band are related in details in this paper. As a kind of dielectric waveguide,the NRD-guide possesses fine transmission performances, and it can be used to fabricate the millimeter wave hyterodyne integrated circuits. The two kinds NRD-guide transmitting front-ends substantiated in the paper, the voltage controlling oscillator(VCO) and twin-Gunn-diode power-combiner,have very similar structures to each other and possess compact sizes, fine machinery and electric performances.For the VCO front-end in Ka-band, the frequency modulation band is greater than 150MHz, the output power is larger than 20mW.For the power-combiner, the output power is larger than 40mW,the combination efficiency is better than 90%,the frequency stabilization reaches 1.68×10^?5. Combined with the receiving front-end reported before,the transmitter and receiver can be composed to a dielectric waveguide R/T module to be applied in some millimeter wave sub-systems.     

Dielectric property measurement using a resonant nonradiative dielectric waveguide structure

This letter describes a new dielectric characterization technique, based on the resonant nonradiative waveguide structure described by Yoneyama and Nishida , for permittivity measurements at microwave and mm-wave frequencies. The measurement system is modeled as a resonator comprised of two parallel conducting plates with a rectangular dielectric slab sandwiched in-between. Resonant frequencies of the longitudinal section electric (LSE) modes and the unloaded Q of the cavity are used to determine the permittivity of the dielectric and its loss tangent, respectively. The technique is shown to be accurate for measuring the dielectric properties of a wide array of polymer and oxide materials. For materials with small dielectric loss tangents, an accuracy of better than /spl plusmn/0.4% is attained in the measurement of the relative dielectric constant of the material.     

Analysis of double-layered nonradiative dielectric waveguide containing a magnetized ferrite

The propagation characteristics of the dominant mode in magnetized-ferrite-loaded double-layered nonradiative dielectric waveguide are studied. The analysis is based on mode-matching method. Numerical results are presented for various values of structure and material parameters.     

Noninvasive pulse modulator concept for nonradiative dielectric(NRD) waveguide

The nonradiative dielectric (NRD) waveguide has been identified as a promising candidate for use at millimetre-wave frequencies. To realise this promise NRD waveguide must support the design of the necessary active and passive components for the realisation of systems and subsystems. The authors describe the principle of a novel modulator for use with NRD waveguide and present preliminary results     

Full-wave analysis of a nonradiative dielectric waveguide with apseudochiral Ω-slab

This paper presents a new microwave device - a non-radiative dielectric (NRD) waveguide with a dielectric pseudochiral Ω-slab - the Ω-NRD waveguide. A rigorous full-wave analysis is presented and the modal equations for the longitudinal-section magnetic (LSM) and longitudinal-section electric (LSE) modes are derived. The dispersion curves and operational diagrams for the first hybrid LSM modes are presented. The effect of the pseudochiral Ω-medium is discussed. New interesting modal features are revealed, showing that the propagation characteristics may differ considerably from the common isotropic case     

基片集成波导K波段平面滤波器研制

利用基片集成波导与传统矩形波导的等效关系,类比矩形波导滤波器理论设计方法,结合三维电磁仿真软件模拟和优化技术,快速设计了K波段基片集成波导带通滤波器。实物测试结果显示滤波器的中心频率为19.75GHz,相对带宽6%,通带内插入损耗为1 dB,带内反射系数小于–14 dB,体积小于6 cm×2 cm×1 cm。相比传统波导形式滤波器,本设计为平面结构,体积小、易于系统集成。     

Reduction of dielectric losses in substrate integrated waveguide

The impact of different loss mechanisms on the attenuation of the substrate integrated waveguide (SIW) is investigated. Using a multilayer PCB technology, an air-cut region is introduced in the SIW structure to reduce the attenuation caused by dielectric losses. Numerical results obtained using a mode-matching technique verify that the attenuation constant of the SIW can be reduced significantly if the width of the air-cut is chosen properly     

Substrate integrated waveguide (SIW) linear phase filter

A planar four-pole linear phase filter centered at 10GHz based on substrate integrated waveguide (SIW) is proposed. The filter is composed of four side-by-side horizontally oriented SIW cavities, which are coupled in turn by evanescent waveguide sections with three direct coupling and one cross coupling between the first and fourth SIW cavities. The SIW cavities are fed by microstrips through coupling slots. A curve-fitting technique is adopted to improve the efficiency of the design process. The measured results are presented and compared with the results simulated by a high-frequency structure simulator. Good agreement between the simulated and measured results is observed.     

一种应用于毫米波波段的基片集成波导滤波器

提出了一种工作于毫米波波段的基片集成波导滤波器,该滤波器在上下金属层刻蚀出哑铃槽结构,通过哑铃槽之间的耦合,极大提高了其带外抑制性。仿真实测结果表明,滤波器的中心频率在30 GHz,通带内相对带宽为39.5%,中心频率插入损耗为1.44 d B,带内回波损耗大于13 d B。滤波器带外衰减陡峭,结构紧凑,实测结果与仿真结果吻合良好。     

Thick-film fabrication techniques for millimetre-wave dielectric waveguide integrated circuits

The letter presents the results of an initial study performed in the development of millimetre-wave dielectric waveguide integrated circuits using novel thick-film printing techniques. The measurements of the propagation characteristics of sample lines at 60 GHz demonstrate the feasibility of such an approach and examples of printed components indicate its potential in low-cost high-volume applications.     

Substrate integrated waveguide elliptic filter with transmission line inserted inverter

A planar waveguide elliptic filter with a transmission line inserted inverter is proposed. This inline filter based on a substrate integrated waveguide is fabricated by the standard PCB process. Simulated results are compared with measured data and good agreement is reported.     

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     

Substrate integrated waveguide loaded by 3-dimensional embedded split ring resonators

A substrate integrated waveguide (SIW) loaded by three-dimensional embedded split ring resonators (3-DESRRs) is discussed theoretically and experimentally. The 3-DESRR structure which has proved to be an alternative magnetic metamaterial resonator for SIW structures is able to provide negative transversal permeability if excited properly. The 3-DESRR loaded SIW shows a bandpass-like response as an effect of loading the 3-DESRRs in the SIW. The lower and upper band edges of the resulting transmission line (TL) are determined by the SIW cutoff (f_c) and the resonance frequency of the 3-DESRRs, respectively. Finally, a prototype of the proposed 3-DESRR loaded SIW TL is fabricated and tested. The measured results are in good agreement with those obtained by theory and simulation.