Characteristics of single and coupled rectangular resonators in suspended substrate stripline

A rigorous spectral-domain analysis is carried out to determine the resonant frequency characteristics of resonators in a general suspended substrate stripline. The resonant frequency characteristics of single as well as coupled rectangular resonators are computed. An important observation for resonators in broadside-coupled suspended substrate stripline is that the even- and odd-mode resonant frequencies are considerably different.     

Comparison between theoretical and measured microstrip gapparameters involving anisotropic substrates

In this paper, experimental results are presented for microstrip symmetrical-gap discontinuities. The experimental technique is based on the measurement of the resonant frequencies of several gap-coupled rectangular microstrip resonators. In particular, gap discontinuities on anisotropic dielectric and two-layer composite substrates have been investigated. Reasonably good agreement has been found in most cases between theoretical data [obtained by means of the excess charge technique in the spectral domain (EC-SDA)] and experimental data, even though the theoretical results have been obtained by using a quasi-static approach     

Full-wave analysis of circular microstrip resonators inmultilayered media containing uniaxial anisotropic dielectrics,magnetized ferrites, and chiral materials

In this paper, Galerkin's method in the Hankel transform domain is applied to the determination of the resonant frequencies, quality factors, and radiation patterns of circular microstrip patch resonators. The metallic patches are assumed to be embedded in a multilayered substrate, which may contain uniaxial anisotropic dielectrics, magnetized ferrites, and/or chiral materials. The numerical results obtained show that important errors can be made in the computation of the resonant frequencies of the resonators when substrate dielectric anisotropy, substrate magnetic anisotropy and/or substrate chirality are ignored. Also, it is shown that the resonant frequencies of circular microstrip resonators on magnetized ferrites can be tuned over a wide frequency range by varying the applied bias magnetic field. Finally, the computed results show that the resonance and radiation properties of a circular microstrip patch on a chiral material is very similar to those of a circular patch of the same size printed on a nonchiral material of lower permittivity     

Microstrip rectangular resonators on ferrimagnetic substrates

The resonant frequency, bandwidth, efficiency and resonant length of a rectangular microstrip resonator on a ferrimagnetic substrate are derived theoretically and are computed for a typical ferrite substrate. The computed values are compared with those of a similar microstrip antenna on a dielectric substrate.     

Analysis of microstrip antennas using moment methods

The method of moments is used to analyze microstrip antennas of rectangular and nonrectangular shape. Surface currents are used to model the microstrip patch and volume polarization currents for the dielectric slab. The method requires unusually precise computation of the impedance matrix but is capable of accurately predicting currents, impedance, and resonant frequency of the antenna.     

Systematic evaluation and analysis for 60-GHz dielectric resonatorscoupled to a microstrip line on a GaAs substrate

This paper presents the first systematic evaluation and analysis of 60-GHz-band TE_01δ-mode cylindrical dielectric resonators coupled to a microstrip line on a GaAs substrate. The loss components of the unloaded Q are analyzed using simple numerical techniques. The distance between the resonator center and the microstrip line which gives the maximum coupling coefficient is found to be approximately 3/5 of the resonator radius, whose ratio is almost constant for all practical cases. The temperature characteristics are also demonstrated and the origins of temperature dependences of the unloaded Q and the coupling coefficient are discussed. An equivalent circuit model for the dielectric resonator coupled to the microstrip line is presented, whose element parameters can express the dependences of the resonant frequency, the unloaded Q, and the coupling coefficient on the structural parameters and the temperature     

Resonance in a superstrate-loaded rectangular microstrip structure

The complex resonant frequency of a superstrate-loaded rectangular microstrip structure is investigated. The study is performed by using a full-wave analysis and Galerkin's moment method. The numerical convergence using sinusoidal basis functions, with and without considering the edge singularity to expand the unknown surface current distribution on the rectangular patch, is discussed. Numerical results for the effects of superstrate permittivity and thickness on the complex resonant frequency of the rectangular microstrip structure are also presented     

Radiation of a rectangular microstrip patch antenna covered with a dielectric layer

The effect of a protecting dielectric superstrate on the radiation pattern of a rectangular microstrip patch antenna is investigated theoretically. The analysis approach is based on the spectral-domain method of moments in conjunction with the stationary phase method. A new concise expression is derived for computing the radiation electric field. The validity of the solution is tested by comparing the computed results with the experimental data. At higher superstrate thicknesses, numerical results indicate that the radiation pattern drastically changes into three lobes. The resonant frequency, on the other hand, increases with the increase of the thickness of the dielectric cover.     

Tunable microstrip resonators with ferroelectric capacitors

The question of increasing the tuning band of microstrip resonators that use ferroelectric capacitors for tuning in the region of increased electric lengths is considered which allows using them in the upper part of the centimeter band (Ku-band, K-band). Band properties of regular and step-irregular resonators operating at the lowest resonant frequency are analyzed.     

Rigorous Full-Wave Analysis of Rectangular Microstrip Patch Antenna on Suspended and Composite Substrates

In this paper, Galerkin’s method in the Fourier transform domain is applied to the determination of the resonant frequencies and half-power bandwidth of rectangular microstrip patch on composite and suspended substrates. Using Galerkin’s method in solving the integral equation numerically, the complex resonant frequency of the microstrip antenna on suspended and composite substrates is studied with sinusoidal functions as basis functions, which show fast numerical convergence. The validity of the solution is tested by comparison of the computed results with experimental data. Finally, numerical results for the effects of suspended and composite substrates on the resonant frequency and half-power bandwidth are also presented.     

Duplexer designed on the basis of microstrip filters using high dielectric constant substrates

A microstrip duplexer for a modification of a PCS communication system operating at frequencies of 1.84?C1.87 and 1.75?C1.78 GHz is described. The duplexer containing microstrip bandpass filters on high dielectric constant substrates (? _r = 92) are compared with duplexers manufactured on microwave ceramic materials with high values of ? _r . The microstrip bandpass filters use stepped-impedance resonators placed one near another with a gap of 0.1?C0.2 mm. It is shown that the microstrip duplexer has slightly lower insertion loss and occupies smaller volume than a duplexer using coaxial dielectric resonators having a rectangular cross section of 3 × 3 mm and ? _r = 92.     

Analysis of a cylindrical-rectangular microstrip structure with anairgap

The resonance problem of the cylindrical-rectangular microstrip structure with an airgap between the substrate layer and the ground conducting cylinder is studied by using a rigorous full-wave approach and a moment method calculation. The resonance condition is satisfied by complex resonant frequencies, which provide the information of resonant frequency and half-power bandwidth of the structure. Numerical results indicate that, with the increasing of the airgap thickness, the half-power bandwidth of the structure at the efficient radiating mode of HE_0.1 is considerably increased, which improves the narrow bandwidth characteristics of microstrip structures. Details of the numerical results, including the results for the planar rectangular microstrip structure with an airgap, are presented and analyzed     

New compact microstrip antenna

A new microstrip antenna geometry with considerable reduction in size, with similar radiation characteristics to those of an equivalent rectangular patch antenna is proposed. A relationship has been suggested for finding out the resonant frequency of the new geometry, and its validity has been established by the experimental results. Without increasing the aperture area, this geometry also offers a facility for considerably reducing the resonant frequency compared to conventional patches     

Resonant frequencies of rectangular microstrip antennas with flushand spaced dielectric superstrates

This paper presents a predictive model for the resonant frequencies of rectangular microstrip antennas with flush and spaced superstrates. This closed-form model is suitable for CAD and is directly applicable for the integration of microstrip antennas beneath plastic covers or protective dielectric superstrates in portable wireless equipment. The model utilizes conformal mapping and the concept of equivalent capacitance to determine the effective permittivity of a covered microstrip structure. A comparison between calculated and measured resonant frequencies demonstrates that the model provides less than 1% errors for structures with low relative permittivities (ε _r<3) and slightly higher errors for structures that contain higher permittivity materials. Generally, the model predicts the resonant frequency of a spaced superstrate structure as accurately as possible within the tolerance range of the structure's electrical and physical parameters     

Gap-coupled microstrip array antenna for wide-band operation

The theoretical and experimental investigations carried out on a gap-coupled microstrip array antenna reveal that there is a significant improvement in VSWR and bandwidth characteristics of the gap-coupled microstrip array antenna as compared with a conventional microstrip array antenna. The input impedance and the resonant frequency of the gap-coupled patch are found to depend heavily on the gap length as well as on the dielectric constant of the substrate material.     

空气隙对矩形微带天线性能的影响

论述了通过引入空气隙来改变矩形微带天线性能。首先,根据修改的微带天线的腔模理论,利用电磁场理论推导了具有空气隙的矩形微带天线的等效介电常数和谐振频率的理论计算公式。然后,考虑了边缘场的影响,引入了有效介电常数,对谐振频率的理论公式进行了修正。同时,应用等效原理和镜像原理推导出辐射方向图。最后,对于空气隙高度为不同数值的情况给出矩形微带天线的谐振频率和辐射方向图的数值结果,与文献实测结果很吻合。     

平面型谐振腔的特性分析

本文应用一般型谐振腔的变分方程,推导了平面型谐振腔谐振频率的特征方程。该方程具有稳定性质,且仅以金属带上的电流为未知参量,因而运算效率高。作为示例,文中数值计算了孤立的、边缘耦合的以及宽边耦合的悬置微带线矩形谐振腔,数值结果与相应文献的计算数据一致。     

Inverted microstrip and suspended microstrip with anisotropic substrates

This letter presents characteristics of the inverted microstrip and the suspended microstrip, with anisotropic substrates. The transverse transmission-line method combined with the mapping method and the variational technique in the space domain are used to analyze the impedance characteristics. The data presented should find application in the design of MIC components at millimeter-wave frequencies.     

Resonant frequency of a rectangular microstrip patch on severaluniaxial substrates

A full-wave analysis for determining the resonant frequency of a rectangular microstrip patch on multiple uniaxial anisotropic layers with or without an anisotropic overlay is presented. Two independent methods are used to derive the immittance matrix for the patch, from which the resonant frequency is determined. They are the Hertz vector potentials and the modified spectral domain immittance approach. Numerical results of the resonant frequency are given for several patch configurations, including cases of a patch on a single anisotropic layer, a patch on a double layer with one layer anisotropic and one layer isotropic, a suspended patch resonator with anisotropic substrate, a patch with anisotropic overlay and a patch on two anisotropic substrates with an anisotropic overlay. Changes in the resonant frequency of up to 58% are reported as n_x/n _y is changed from 1.0 (for isotropic substrates) to 2.0     

Analysis of microstrip resonators of arbitrary shape

A space-domain approach based on a mixed-potential integral equation formulation is developed for efficient computation of complex resonant frequencies of laterally open microstrip-pitch resonators of arbitrary shape. The effects of the substrate-which may consist of any number of planar, possibly uniaxially anisotropic, dielectric layers-are rigorously incorporated in the formulation by means of the vector and scalar potential Green's functions. The current distribution on the conducting patch is approximated in terms of vector basis functions defined over triangular elements. Computed resonant frequencies, quality factors, modal currents, and far-field radiation patterns are presented for several microstrip resonators. For patches of simple, regular shapes, the results are in agreement with published data obtained by specialized techniques, which, unlike the method presented here, are not easily extendible to arbitrary shapes