Coupling suppression in microstrip lines using a bi-periodicallyperforated ground plane

A perforated ground plane is used to suppress the coupling between adjacent and intersecting transmission lines. Experimental results indicate 40-dB suppression of broadside coupling between two adjacent 50-Ω lines. A new option in the design of circuit routing schemes is proposed by demonstrating 28-dB coupling reduction between two intersecting 50-Ω lines     

Propagation and coupling characteristics of microstrip lines withlaminated ground plane

In this paper, we analyze the effect of laminated ground plane on the propagation and coupling characteristics of microstrip lines. Each lamina is modeled as an anisotropic layer, and transition matrix is used to relate the tangential field components in different laminae. An integral equation is formulated in the spectral domain, and the Galerkin's method is applied to solve the integral equation for the phase and the attenuation constants of several microstrip line structures. The effects of substrate dielectric are also studied. The attenuation constant variation thus obtained will be useful in circuit board design and in studying signal transmission in lamina environment     

Characterisation of aperture coupled microstrip patch antenna withthick ground plane

The feasibility of using a thick ground plane with an aperture coupled microstrip patch antenna while maintaining reasonable antenna performance is demonstrated using moment method and reciprocity analyses in the spectral domain. The thick ground plane, which may serve as a heatsink for active MMIC circuitry, or as a mechanical support for thin substrates, is particularly advantageous in millimetre wave phased array applications. It is found that the effect of ground plane thickness is to reduce the level of coupling from the feed line to the patch     

Gain enhancement of a circularly polarized equilateral-triangular microstrip antenna with a slotted ground plane

A novel circular polarization (CP) design of a single-feed equilateral-triangular microstrip antenna with enhanced antenna gain is presented. This CP design is obtained by placing three triangular slots at properly locations below the equilateral-triangular radiating patch in the ground plane. By adjusting one of the triangular slot's side lengths slightly longer than that of the others, two orthogonal near-degenerate resonant modes for CP radiation can be excited. Measured antenna gain in this study can easily be increased by 3.3 dBi (5.1 dBi versus 1.8 dBi), as compared to the same height, substrate material, operating frequency and radiating patch shape of a regular equilateral-triangular microstrip antenna without triangular slots in the ground plane. Prototype antenna is fabricated for experimental evaluation. Simulated and measured results are presented.     

Rectangular microstrip patch antennas with infinite and finite ground plane dimensions

The rectangular microstrip patch antenna has been extensively analyzed with regard to its input impedance and resonant frequency, both for infinite and finite ground plane dimensions. For infinite ground planes existing formulas have been compared and improved parameters presented. The influence from the side current radiation has been discussed as well. For finite ground plane dimensions the contribution from the ground plane edge diffraction has been accounted for in an equivalent radiation conductance and an equivalent diffraction susceptance. Formulas for these parameters have been developed on the basis of different theories. They are valid under the condition that only one of the ground plane dimensions are finite at the same time. Experimental investigations are carried out to test the accuracy of the developed formulas, showing good accuracy under the given conditions.     

Compact stub type microstrip bandpass filter using defected ground plane

Usually a defected ground plane structure (DGS) provides only a band-reject response. However, in this work we introduce a simple band-accept circuit element in the DGS and developed a microstrip stub type compact 3-pole bandpass filter (BPF) at 4.2 GHz. The BPF has bandwidth and insertion loss 38% and 0.6 dB respectively. It has better than 25 dB rejection in the stopband up to 12 GHz.     

采用EBG地的低剖面微带定向天线设计

对具有金属地的微带定向天线,低剖面设计面临着工作频带窄的难题。采用蘑菇形EBG结构代替微带定向天线的常规金属地,利用EBG地对特定频率电磁波的同相反射特性,在保持天线工作频带条件下,缩减天线微带基板的厚度,实现低剖面设计。以一只工作频点为5.8 GHz的2×2微带阵列天线为例,该阵列天线的辐射单元采用分形结构以进一步提升天线带宽。仿真计算和实际测试表明:该微带阵列天线在采用低剖面设计后,微带基板厚度由原1.0 mm降至0.25 mm,而天线的定向辐射方向图、增益和工作带宽基本保持不变。     

A simple and accurate model for microstrip structures with slotted ground plane

A simple and accurate circuit model for microstrip filtering structures with slotted ground plane is presented. The unit cell model consists of a series inductance and shunt capacitance for the microstrip line, an ideal transmission line characterized by its impedance and electrical length for the slot, and an ideal transformer to model coupling to the slot. The coupling mechanism to the slots resonances and subsequent emergence of transmission gaps is explained for different positions of the microstrip line. Excellent agreement with measurement is demonstrated over the broad bandwidth of dc to 20 GHz.     

A simple and accurate model for microstrip structures with slotted ground plane

A simple and accurate circuit model for microstrip filtering structures with slotted ground plane is presented. The unit cell model consists of a series inductance and shunt capacitance for the microstrip line, an ideal transmission line characterized by its impedance and electrical length for the slot, and an ideal transformer to model coupling to the slot. The coupling mechanism to the slots resonances and subsequent emergence of transmission gaps is explained for different positions of the microstrip line. Excellent agreement with measurement is demonstrated over the broad bandwidth of dc to 20 GHz.     

The finite ground plane effect on the microstrip antenna radiation patterns

The uniform geometrical theory of diffraction (GTD) is employed for calculating the edge diffracted fields from the finite ground plane of a microstrip antenna. The source field from the radiating patch is calculated by two different methods: the slot theory and the modal expansion theory. Many numerical and measured results are presented to demonstrate the accuracy of the calculations and the finite ground plane edge effect.     

Compact dual-frequency linear antenna with partial ground plane

In order to meet the need of multiband and antenna-in-package (AiP), a compact dual-frequency antenna with a partial ground and linear structure is proposed, optimised and realised. The proposed antenna was designed at 2.4 GHz and 5.8 GHz bands for WLAN applications. The total size of the antenna is 20 mm × 20 mm, equals to 0.27 λ_g1 × 0.27 λ_g1 and 0.65 λ_g2 × 0.65 λ_g2 (λ_g1, λ_g2 are the microstrip (with ground) guiding wavelengths at 2.4 GHz and 5.8 GHz) or 0.15 λ₀₁ × 0.15 λ₀₁ and 0.38 λ₀₂ × 0.38 λ₀₂ (λ₀₁, λ₀₂ are the wavelengths in the atmosphere at 2.4 GHz and 5.8 GHz). Also, omnidirectional radiation characteristics in the desired bands can be obtained.     

Design and analysis of microstrip photonic band gap filter without etching ground plane

A design of microstrip photonic band gap (PBG) filter is presented in this paper. The band reject filter is compact in structure and provides accurate band gap. The proposed filter has a periodic configuration; the impedance distribution over the length of each period is varied according to a designated sinusoidal function. Both theoretical and experimental results indicate that a bandstop filter with an extremely wide bandwidth can be achieved. Detailed analysis of the frequency response of the PBG filter is carried out in this paper.     

Improvements in the performance of microstrip antennas on finite ground planes through ground plane edge serrations

This paper explores how edge serrations on a truncated ground plane affect the performance of a microstrip antenna. The investigation includes both simulations and measurements of a range of serration dimensions. Improvements in performance through ground plane edge serration include lower cross-polarization level, increased beam width, and slight impedance tuning compared to a microstrip antenna on a simple finite ground plane.     

Multi-band modified fork-shaped microstrip monopole antenna with ground plane including dual-triangle portion

A modified fork-shaped microstrip monopole antenna with the ground plane including a dual-triangle portion is studied experimentally to obtain a large bandwidth and a multi-band characteristic. In this case, the ground plane including a dual-triangle portion leads to improving the impedance matching for a lower band. Although the use of a high relative permittivity (/spl epsiv//sub r/=4.3) substrate usually restricts the operation bandwidth, the radiation resistance also was a low value. The 2.0 VSWR impedance bandwidth is 29.8% (731-987 MHz) for a lower band, and 90.2% (1498-3080 MHz) for a higher band operation. This single-layer microstrip monopole antenna also retains a low and a thin profile characteristic.     

Influence of the ground plane structure on the radiation pattern of microstrip antennas

Most radiation analyses of microstrip antenna are based on the assumption of an infinite ground plane. Actual environments are different, and the ground plane is necessarily limited. In this paper, we show the influence of the dimensions and the shape of the support. Analytical formulations are explicitly given. Many comparisons between theory and experimentation are presented. Next, we apply the previous results to the case of a circularly polarized antenna, in order to optimize the ellipticity ratio.     

Compact microstrip lowpass filter using shunt open stubs and coupled slots on ground plane

A compact microstrip lowpass filter with prominent cutoff sharpness and very wide stopband is presented. The microstrip lowpass filter is composed of a transmission line with shunt open stubs on the topside of the microstrip structure and coupled slots on the ground plane. The shunt open stub microstrip filter with slots on the ground plane has a wide stopband at high frequency, and the coupled slot on the ground plane has sharp cutoff response at low frequency. The combined characteristics of these structures make for an excellent lowpass filter performance.     

Coupling between microstrip lines with finite width ground plane embedded in thin-film circuits

Three-dimensional (3-D) interconnects built upon multiple layers of polyimide are required for constructing 3-D circuits on CMOS (low resistivity) Si wafers, GaAs, and ceramic substrates. Thin-film microstrip lines (TFMS) with finite-width ground planes embedded in the polyimide are often used. However, the closely spaced TFMS fines are susceptible to high levels of coupling, which degrades the circuit performance. In this paper, finite-difference time domain (FDTD) analysis and experimental measurements are used to demonstrate that the ground planes must be connected by via holes to reduce coupling in both the forward and backward directions. Furthermore, it is shown that coupled microstrip lines establish a slotline type mode between the two ground planes and a dielectric waveguide type mode, and that the connected via holes recommended here eliminate these two modes.     

Internal inductance and conductor loss associated with the groundplane of a microstrip line

In previous work, a closed-form expression for the current density on the ground plane of a microstrip line was presented. In this paper, we show how this formula for the current density is used to derive an expression for the internal inductance associated with the ground plane. Results are presented for different geometries that illustrate when the internal inductance of the ground becomes comparable to the external inductance of the microstrip line. We also illustrate that the integrals needed for the internal inductance calculation can be used to develop an expression for the conductor loss associated with the ground plane     

Capacitance, inductance and effective relative permittivity of microstrip line

The capacitance and inductance of the open microstrip line are found in explicit form for narrow and wide microstrips and for very large substrate permittivity. For an arbitrary width, the integral equation is transformed into an infinite set of algebraic equations, which can be handled by computer. Hence the effective relative permittivity at low frequencies can be found.     

The inductance model of coupled high-Tc superconducting microstrip lines

A simple analytical model of odd and even mode external inductance and kinetic inductance for coupled high-temperature superconducting (HTS) microstrip lines is developed. The kinetic inductance model is derived with the extended incremental inductance rule which is applied in a different way for different conductor thickness. The odd and even mode inductance, self- and mutual inductance, characteristic impedance, and attenuation constant are computed with the presented model expressions and the results agree well with that in published literature.