U shaped slot and Spiral shaped Monopole Antenna with Defected Ground Structure for Wireless Applications

Abstract

- A novel compact U shaped and spiral shaped Periodic slotted antenna with Defected
Ground structure (DGS) used for Wireless and satellite communication applications is investigated
and proposed. The proposed antenna resonates at three separate frequencies to cover 3.5 GHz
(WLAN), 5.4 GHz (Wi-MAX) and 7.4 GHz (Fixed satellite), keeping the overall size compact of
36x36x1.6 mm3
using a substrate FR-4 of permivitivity of ?r = 4.4. The proposed microstrip Patch
Antenna (MSPA) consists of a square radiator in which a U shaped and spiral slots are etched out
along with square defects on half ground surface and a microstrip feed line. The U shaped slots and
spiral one with DGS modifies the total current path thereby making the antenna to operate at three
useful bands. Structure displays the impedance bandwidth of 5.157% (3.4-3.58GHz), 2.9% (5.38-
5.54GHz) and 12.8% (7.22-8.21GHz) with gains 2.5, 4.2 and 5.8 db respectively. The performance
of an antenna is analyzed using parametric optimization techniques, surface currents and field
distributions. Good agreement is achieved between simulated and measured results