S. K. Parui

Bandwidth enhancement of microstrip antennas using shifted parasitically coupled planar multiresonators

In this paper, a wideband planar multi resonator antenna with parasitic coupling is proposed and studied. Impedance and radiation characteristics of this antenna are presented and discussed. From the results, it has been observed that, the Impedance bandwidth, defined by 10dB return loss, can reach an operating bandwidth of 251 MHz with center operating frequency of 3023 MHz, which is about four times that of conventional reference patch antenna. The gain of studied antenna is also observed with peak gain of about 8.33dBi.

HMSIW-Based Miniaturized Sensing Antennas for S- and C-Band Applications

In this letter, half-mode substrate integrated waveguide (HMSIW)-based low profile, rectangular slit(s) loaded compact semicircular antennas are presented as sensors to operate in the S- and C-band. The parent sensor is a HMSIW antenna initially designed at the center frequency of 5.22GHz with a gain of 6.4 dBi for the IEEE 802.11a WLAN U-NII low-band application. The semicircular antenna has metallic vias all along the semicircular edge, thereby making it perfect electrical conductor wall while the other side devoid of vias is a perfect magnetic conductor (PMC) wall. It is miniaturized upon placing rectangular slit(s) along the PMC edge, which reduces the fundamental resonant frequency to 4.68GHz and further to 3.85GHz with single and double slits, respectively. Both antennas radiate linearly polarized wave corresponding to TM010 mode with respective gain of 5.2 and 4.6 dBi. The antenna prototypes are fabricated using Arlon AD270 substrate and good agreement between simulated and measured results are obtained.

Mutual coupling reduction of microstrip antenna arrays using rectangular split ring shaped defected ground structure

In this paper a study on reduction of mutual coupling of two element microstrip antenna array with rectangular split ring shaped defected ground structure(DGS) is presented. The proposed DGS antenna is simulated by MOM based IE3D simulation software. An observation is made on S12 by changing the dimension of the defects and distance between the antenna array elements. The proposed antenna has a maximum 13.54 dB reduction of mutual coupling while dimension of DGS and distance between antenna elements are properly optimized. This antenna array is operated at 2.4 GHz with a gain of 7.01 dBi in the broadside direction.

Design of a dual polarized rectangular patch antenna using DGS

This paper presents a high port isolation dual frequency orthogonally polarized rectangular patch antenna integrated with defected ground structure (DGS). A spiral-shaped DGS-integrated microstrip line enhances the port isolation of the antenna, while feeding the 2.45 GHz port, port-1 to the antenna and filtering out 3.0 GHz receiving signal from port-2. Similarly a rectangular shaped DGS-integrated microstrip line enhances the port isolation of the antenna, while feeding the 3.0 GHz port, port-2 and filtering out the 2.45 GHz signal from port-1. The microstrip line at two different ports integrated with DGS restricts the highorder harmonics signals coming from transmitter or receiver. The patch is excited through microstrip feed line of 75Ω line impedance. DGS-integrated microstrip line offers image impedance of 150Ω and it is controlled by DGS geometry. An experiment of investigating isolation between the ports has been performed by employing with and without DGS. Measurements show an improvement of more than 25dB in the port isolation when DGS integrated microstrip antenna.

Coplanar waveguide fed wide band modified rectangular slot antenna for UWB applications

In this paper, a Co-planar waveguide (CPW) fed wide bandwidth slot antenna is proposed for UWB applications. The antenna consists of a rectangular slot modified at both side of the CPW feed forming two symmetrical step like ground structure. The proposed antenna structure is simulated by using Finite element Method based ANSOFT HFSS electromagnetic simulation software and characterized by return loss, radiation pattern and gain response. The proposed antenna exhibits an impedance bandwidth from 3.46 GHz to 10.48 GHz that gives a fractional bandwidth of 101% with return loss less than or equal to 10 dB (VSWR≤ 2). The maximum available gain is 4.5dBi in the broad side direction.

Design of a novel bandstop filter using log periodic based circular split ring slots

Compact planar microstrip bandstop filters are introduced here. These filters consist of log-periodic based 3 resonator elements. These defects or slots on the signal plane effecting resonant frequency of the filters due to increment of slow wave factor, which exhibits good bandstop characteristics. The filters can be designed to function in a low frequency to a very high frequency range depending upon the physical dimension of the slots. When the filters are designed at lower frequency, the guided wavelength is increased by increasing the radius of the split ring slots and vice versa. First of all a unit cell is investigated. A set of circular split ring slots are designed to achieve stopband of the filter at desired frequency range.