Transmission line analysis of nonlinear slot coupled microstrip antenna

The transmission line method is used for the analysis of microstrip antennas fed by several nonlinear slots with 'H' shapes or new geometries. This analysis allows the input impedance of nonlinear slot coupled microstrip antennas to be calculated for the four different structures.<>     

Problem-matched basis functions for microstrip coupled slot arrays based on transmission line Green's functions (TLGF)

Problem matched basis functions are proposed for the method of moments analysis of printed slot coupled microstrips. The appropriate equivalent currents of the integral equation kernel are represented in terms of two sets of entire domain basis functions. These functions synthesize on one hand the resonant behavior of slots, microstrips or dipoles and on the other hand the field in proximity of the feeding source and of the discontinuities. In order to define these basis functions, canonical geometries are identified, whose Green's functions have been found in semi-analytical form. The accuracy and the effectiveness of the method in terms of convergence rate and number of unknowns is demonstrated by comparison with a standard fine meshing full-wave analysis. The method is extremely convenient for large arrays, where the subwavelength details should be treated together with large global dimensions. Since the proposed solution is independent of the dimensions of these details, it provides dramatic reduction of the number of unknowns and improvement of condition number.     

Analysis of coupled slot resonators of complex shape in metalization plane of a micro-strip transmission line using the transversal resonance techniques

The transverse resonance techniques is developed for analyzing three-layer planar structures based on micro-strip transmission line with slot resonators of complex shape in the grounding plane. Development of the techniques consists in considering higher space harmonics of current density in the strip line and mutual coupling between the slots in the grounding plane when numerically solving the boundary problem. In order to verify the techniques we conduct analysis of structures that consist of two coupled U- and symmetrical H-shaped slot resonators in the grounding plane of the micro-strip transmission line.     

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.     

Spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators

In this letter, spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators (SRRs) is demonstrated for the first time. By etching SRRs in the upper substrate side, in close proximity to conductor strip, strong magnetic coupling between line and rings arises at the resonant frequency of SRRs. This inhibits signal propagation in the vicinity of that frequency, allowing the rejection of undesired passbands by properly tuning SRRs. To test this novel technique, we have designed and fabricated two different SSRs-based filters. In one case, the rings have been designed to suppress only the first spurious band, and SRRs have been etched at both sides of the 50-/spl Omega/ access lines. For the other prototype, SRRs have been etched on the active device region (i.e., surrounding the parallel coupled lines) and have been tuned to eliminate the first and second undesired bands. The measured frequency responses for these devices confirm the efficiency of this technique to suppress frequency parasitics, with rejection levels near 40 dBs, leaving the passband unaltered. Since SRRs are small particles (with sub-wavelength dimensions at the resonant frequency), this approach does not add extra area to the final layouts. Moreover, the conventional design methodology of the filters holds.     

Effects associated with radiation in coupled halfwave open-circuit microstrip resonators

Measurements, supported by an approximate theoretical prediction, show that the radiation loss in a coupled micro-strip-resonator system can vary greatly between the different modes of resonance. The implications for the realisation of filter networks are indicated; in particular, the effects of radiation loss cannot be represented by a simple reduction of the unloaded Q factor of the individual resonators.     

Compact left-handed microstrip line based on multiple layered step impedance resonators

A novel compact left-handed (LH) microstrip transmission line is presented. To establish a negative permeability and permittivity, the transmission line is loaded with step impedance resonators (SIRs) and an array of thin wires on dual-layer architecture. Compared to existing LH structures, which incorporate conventional split ring resonators (SRRs), the proposed structure is three times smaller in size whilst achieving the same performance. To illustrate the electromagnetic properties of the metamaterial, both analytical and full wave analysis were performed and utilized to determine the effective electromagnetic parameters of the proposed structures. The experimental results show that a microstrip line periodically loaded with SIR only produces a rejection of ?6?dB at a resonant frequency of 5.50?GHz. The results also indicate a pass-band response for a left-handed microstrip line (LHML) constructed from SIR and thin wire arrays at the same resonant frequency.     

基于左手传输线的双线极化微带阵列天线

基于左手传输线,提出了一种新型串联馈电的双线极化微带阵列天线结构.通过上层微带线边馈和下层小孔耦合馈电的方式分别实现了天线单元的垂直极化和水平极化的激励,进而使得该天线单元具有高极化隔离度、低交叉极化和宽频带工作等优点.同时由于左手材料具有相位超前的特性,利用传统的右手微带传输线和左手微带传输线的组合以达到零相位延迟,实现了对上述单元构成的微带阵列天线的串联馈电.相对于传统微带阵列天线,该阵列天线结构简单、面积小、插入损耗小、阵列效率高、易于扩展成更大的平面阵列.     

宽频带微带传输线巴伦的研究

对具有宽频带特性的微带传输线巴伦进行了研究,并应用微波网络优化理论对其进行了详细的理论分析与设计,数值计算结果与有关文献一致。最后,设计并制做了具有十倍频程的微带传输线巴伦,举例说明了本文方法的有效性。     

External Qe of an ellipsoidally shaped ferrimagnetic resonator coupled to strip and microstrip transmission line

Equations are presented for the external Qe of a ferrimagnesic resonator coupled to strip and microstrip transmission line. Experimental data indicate that the equations are accurate to within the measuring system's error.     

On the double nature of transmission zeros in microstrip structures

The EM nature of transmission zeros in microstrip structures has been the subject of several discussions. A liquid crystal thermal mapping technique is used for detecting the magnetic field distribution inside rectangular structures at the frequencies of the transmission zeros. In this way a perceptible evidence is given to previous theoretical results, which have pointed out the existence of two types of transmission zeros, called modal zeros and interaction zeros.     

Quality of tunable transmission line resonators with capacitor

A formula for the quality of microwave resonators containing a segment of a transmission line and a capacitor is obtained. The formula includes the qualities of the transmission line and capacitor and the sensitivity of the resonance frequency of the resonator to capacitance variation. It provides for the control of the resonator quality and insertion loss of bandpass filters with such resonators in the course of tuning. Analysis based on this formula extended understanding of the character of the resonator quality behavior under electric length variation.     

Performance of the transmission line model for the microstrip elements

Although more rigorous treatments have been developed for the microstrip elements, the purpose of this transmission line model is to provide a numerically efficient substitute for them. The rectangular resonator is replaced by two equivalent radiating slots. In most practical cases the approximations are acceptable. It is obvious that the efficiency of the transmission model can be used to include mutual coupling in practical analysis. The calculated results are in good agreement with observed results.     

Propagation characteristics of microstrip transmission line on ananisotropic material ridge

A microstrip transmission line residing on an electrically anisotropic material ridge embedded in a multilayered environment is studied using a coupled set of integral equations (IE's). The full-wave IE formulation easily accommodates arbitrary material anisotropy and inhomogeneity in the finite ridge region using equivalent polarization currents residing in a multilayered isotropic background. New results are presented for uniaxially anisotropic ridge structures which show that the transmission line propagation constant is sensitive to anisotropy for certain ridge structures and insensitive for others, compared to the conventional line on an infinite substrate. Results are also presented for a transmission line printed on a nonreciprocal solid-state magnetoplasma ridge. The current distribution associated with the dominant microstrip mode is investigated, where it is found that the transverse component of current is much larger for the ridge geometry than for the infinite substrate case, although the transverse component is still small compared to the longitudinal component     

Compact frequency and bandwidth tunable stopband filters using split ring resonators and varactors coupled transmission line

Two highly compact tunable stopband filters using microstrip transmission lines coupled with split ring resonators (SRRs) and varactor diodes are presented. Frequency or bandwidth tuning capability of each device is demonstrated. The frequency tunable filter, realized by a single stage, shows a wide tuning range of 19.8% with a maximum bandwidth of 5% and an insertion loss of approximately 20 dB at 4 GHz. The bandwidth tunable filter, realized by double stages, shows a 10-dB bandwidth of 19–34% with a biasing voltage of 0–10 V. The implemented frequency tuning and bandwidth tuning devices show a significant area reduction of 60.1% and 53.5%, respectively, in comparison with a similar frequency or bandwidth tunable structure presented by others. Equivalent circuit models are presented. The measured S-parameters are in good agreement with simulated ones.     

End effects in coupled rectangular resonators in unilateral fin line

Spectral domain analysis is used to determine the end effects in coupled rectangular slot resonators in unilateral fin lines. End corrections computed as a function of the structural parameters are reported.     

Realization of four transmission zeros in a four-pole superconducting microstrip filter using cross-shaped spiral resonators

The realization of four finite transmission zeros with high-temperature superconducting microstrip narrow-band bandpass filter using four cross-shaped spiral resonators is described for the fully canonical case. The approach is based on the "N+2" transversal coupling matrix, which is composed of main direct coupling as well as source/load coupling. The filter, with 0.75% bandwidth, 3.25 MHz, at 408-MHz band, is to be used for a radio astronomy application at Jodrell Bank Observatory, U.K. The measured results match well with both theoretical results and simulated results, except for a small center frequency offset.     

Longitudinal field components and frequency-dependent phase velocity in the microstrip transmission line

Two methods for the calculation of the fields in a microstrip transmission line are presented. Longitudinal field components and the dependence of phase velocity on frequency are considered. Some fundamental effects are discussed and are demonstrated numerically and experimentally by an example.