Y. K. Awasthi

Equivalent isotropic relative permittivity of microstrip on multilayer anisotropic substrate

A closed-form model to obtain the equivalent isotropic relative permittivity of the multilayer microstrip line on the anisotropic substrate for 0 w/h ≤ 10, anisotropic ratio 0.5 ≤ n ≤ 3 for both low and high permittivity substrates is reported. The model has accuracy 0.5% against the full-wave method. It computes effective relative permittivity and characteristic impedance of microstrip on composite anisotropic substrates with deviations 5.3% and 1.78%, respectively against the EM-software Empire. It is used to obtain dispersion in multilayer anisotropic substrate microstrip up to millimetre wave range with high accuracy against the results of HFSS.

Microstrip patch antenna with defected ground structure & defected microstrip structure

In this paper we propose the antenna geometry to design a very compact microstrip patch antenna using thin dielectric substrate having low dielectric constant. This antenna provide better efficiency, better band-width without any enhancement in the weight, volume or cost. HFSS high frequency simulator is employed to analyze the proposed antenna and simulated results on return loss, the E-and H-plane radiation pattern is presented. The antenna parameter in frequency domain analysis has been investigated to show its capability as an effective radiating element. Due to low-profile structure it used in the wireless application.

Design of Compact Flower Shape Dual Notched-Band Monopole Antenna for Extended UWB Wireless Applications

Abstract In this letter, a compact monopole antenna for ultra wideband (UWB) applications is proposed with small size of 18×20=360 mm2. Antenna consist of a flower shape radiating patch with a pair of C-shaped slots which offer two notch bands for WiMAX (3.04–3.68 GHz) & WLAN (4.73–5.76 GHz) and two rectangular shaped slots in the ground plane which provides a wide measured usable fractional extended bandwidth of 163 % (2.83–14.0 GHz) with improved VSWR. Moreover, it is also convenient for other wireless application as close range radar, 8–12 GHz in X-band. Measured radiation patterns exhibits nearly omnidirectional in H-plane and dipole like pattern in E-plane across the bandwidth and furthermore exhibits good time domain performance.

Compact planar UWB monopole antenna with dual band-notch characteristics

In this article, a compact Mickey shaped monopole UWB antenna is presented with dual notch band characteristics. The proposed antenna VSWR (<2) and return loss (<-10 dB) results have been verified by EM simulator and the measured impedance bandwidth covers from 2.88 GHz to 12.11 GHz which confirms the bandwidth. Furthermore, the two notched bands, i.e., WiMAX (3.3-3.7 GHz) along with C band (3.7-4.2 GHz) and WLAN (5.15-5.825 GHz) are band rejected so that the interference is mitigated in the existing wireless system. The proposed antenna is fabricated with compact dimensions of 20 × 20 mm² = 400 mm² on FR4 substrate with permitivity 4.4 and thickness of 1.6 mm. The measured gain and radiation characteristics of proposed antenna provide best results showing omni-directional pattern in H-plane and dipole like pattern in E-plane.

Very Sharp Compact Microstrip Lowpass Filter

This paper presents a design of very sharp compact micro strip low pass filter. Performances of the filter are compared with elliptic LPF and DGS based LPF. Performances are, Sharpness of the filter is 121.4dB/GHz, 20dB stop band rejection up to 3fc, insertion loss in pass band is 0.17dB. Size of the LPF is 33% smaller than elliptic and DGS based LPF. Such type of filter could be used in modern communication systems.

Analysis of dual-band bandpass wireless filters using hairpin resonator by transmission line model

This paper presents a microstrip dual band band pass filter using two hairpin resonators with symmetric and asymmetric feed lines. A simple transmission line model is used to determine the two transmission zeros for the two hairpin resonator structure. The locations of transmission zeros are at the fundamental and higher mode resonances. The analysis is done through MATLAB and the equivalent circuits have also been verified. The dual-band bandpass filters with the bandwidths of 50MHz and 100 MHz have been designed with centre frequencies of 5.7 GHz and 6.9 GHz respectively. The filter shows different bandwidth for different lengths with the same coupling gap. More bandwidth is available for high insertion loss and vice-versa. Also, this filter with compact size shows a sharp pass band and lower insertion loss due to less number of coupling gaps. To obtain high selectivity of the filter, cascading structure of the filter can also be further developed.

Circuit Model of Multilayer Microstrip Step Discontinuity Using Single-Layer Reduction Formulation

Abstract New closed-form models for the microstrip step discontinuity to compute shunt capacitance (Cp) and series inductance (Ls) is reported for the substrate 2.3 ≤ ϵr ≤ 40.0 or more. The model is extended to the multilayer (composite and suspended substrate) microstrip step discontinuity. The average deviation for normalized Cp is 5%, and normalized Ls are 2.9 against the results extracted from Sonnet. For the multilayer step discontinuity, the average deviation in the present model for Cp is 5.2%. The method of moment analysis gives an average deviation of 13.53% for Cp and 5.3% for Ls against the results of Sonnet. Comparison with Sonnet indicates that the static model for simple and multilayer case is valid for h/λ ≤ 0.42.

Pulse propagation on Microstrip transmission-line uUsing an anisotropic substrate

This paper describes the effect of anisotropy on the pulse propagation in microstrip like structures for 0 Lt w/h les 10 anisotropic ratio 0.5 les n les 3 for both low and high permittivity substrates. The anisotropic substrate is transformed into an electrically equivalent isotropic substrate such that the line capacitance in both cases is identical. Using this dispersion model of anisotropy for all anisotropic substrate, shows the behavior of the transient signal propagating on the microstrip transmission line based components and shows how can control the distortion [7], amplitude, ringing, and pulse shape of the transient signal [10].