Wideband DGS Circular Ring Microstrip Antenna Design Using Fuzzy Approach With Suppressed Cross-Polar Radiations

Abstract

Abstract-This paper presents a novel design of a circular ring defected ground structure (DGS) antenna for bandwidth enhancement using fuzzy logic approach. The ground plane of the antenna is defected by introducing circular ring sector type of defect beneath the circular ring patch. The position of the defect in the ground plane to attain the highest return loss and corresponding frequency is determined by using Fuzzy Inference System (FIS). The antenna resonates in X-band showing wideband characteristics with improved gain and reduced cross polar components. The return loss and analogous frequency obtained from simulated results and fuzzy system are compared and are in good agreement. The return loss and input impedance is measured experimentally and compared with the simulated results. Parameters like impedance bandwidth, VSWR and antenna gain are likewise calculated and discussed. The simulated results for the radiation pattern of the proposed design with polarization (Co-polar and Crosspolar) are also presented. The simulated impedance bandwidth of about 1.33 GHz (1.2 GHz experimentally) in X-band is obtained with a gain of 6.43 dB and also cross-polarized radiations have an isolation of 20 dB.

Design of high gain/directional ultra-wideband antenna for radar imaging systems

“…Therefore, 86% fractional bandwidth ((| S 11 | < −10 dB) is achieved in the frequency band of 4.4‐11 GHz by combining resonance frequencies of 4.5, 6, 7, 8, 9.3, and 10.2 GHz. Hence, the proposed antenna is appropriate for UWB operation when compared with earlier designed antennas . The calculated impedance bandwidth (IBW) and variation in return loss among different resonance frequencies with semi‐elliptical axes locations are given in Table .…”

“…Sharma et al proposed a wideband having 50 × 50 mm 2 substrate size circular ring antenna, which cover the frequency range of 8‐12 GHz with low gain. Recently, the directional UWB antenna is designed with DGS or slotted ground structure for airborne radar, microwave imaging, C, X‐bands operation and compared with other reported antennas but these antennas are large in size . Furthermore, Wang et al designed a bow‐tie directional antenna with pyramidal reflector for UWB radar imaging systems.…”

“…Thus, the deviation of slot length/width in ground can increase/decrease the effective inductance and capacitance of antenna. 14,15 Sharma et al 16 proposed a wideband having 50 × 50 mm 2 substrate size circular ring antenna, which cover the frequency range of [8][9][10][11][12] GHz with low gain. Recently, the directional UWB antenna is designed with DGS or slotted ground structure for airborne radar, microwave imaging, C, X-bands operation and compared with other reported antennas but these antennas are large in size.…”

“…Recently, the directional UWB antenna is designed with DGS or slotted ground structure for airborne radar, microwave imaging, C, X-bands operation and compared with other reported antennas but these antennas are large in size. 16,17,[21][22][23][24] Furthermore, Wang et al 18 designed a bow-tie directional antenna with pyramidal reflector for UWB radar imaging systems. This antenna is highly directional but acquires less bandwidth of 1.6-4.2 GHz and size of reflector 110 × 90 mm 2 is much large.…”

Wideband High Gain Fractal Antenna for Wireless Applications

“…The use of fractal geometries helps in improving several antenna features. Many DGS (Defected Ground Structure) structures have been proposed for improving parameters of antennas by incorporating DGS in the form of slots with dumbbell-shape, Ishape, U-shape and elliptic shape [20,21]. Tuning of DGS structure is most important part of antenna design for achieving wideband applications.…”