The purpose of this work is to miniaturize a rectangular patch antenna which resonates at 2.4 GHz. To achieve this, we present a new geometry of a pi-shaped slot with three annular rings as a Defected Ground Structure (DGS). DGS is a periodic etched structure or aperiodic sequence of configurations, and it has been used to switch the resonance frequency from starting value 13 GHz to an ending value at 2.4 GHz without any changes in the areas of the actual rectangular microstrip patch antenna (RMPA). The proposed antenna is structured on an FR-4 substrate with thickness 1.6 mm and permittivity 4.4. The general size of the ground plane is 34 × 34 mm 2 . Using the optimal position and dimension of the pi-shaped slot on the ground, the resonant frequency is reduced to 2.4 GHz, which signifies an 81.53% decrease. Proposed antennas with and without DGS are simulated by using High-Frequency Structure Simulator (HFSS) and Advanced Digital System (ADS) Agilent technology, fabricated, and measured for Wireless Local Area Network (WLAN) application.

The main intention to present this work is to miniaturize and gain enhancement of a tapered microstrip patch antenna, which resonates for Global Positioning System (GPS) of L1 band at 1.575 GHz. To accomplish this, we present a new design configuration of a Tap-Shaped Defected Ground Structure (TSDGS). It has been utilized to switch the resonant frequency from 14.5 GHz to 1.575 GHz with no adjustment of areas of the actual Tapered Microstrip Patch Antenna (TMPA). The prototype antenna is fabricated on a Roger RT Duroid substrate merely 58 × 22 mm 2. Conclusively, a miniaturization allowed up to 89.31%, with regard to the TMPA, is excellently accomplished. The gain of the proposed antenna is successfully enhanced with properly locating the metamaterial superstrate onto the basic patch antenna. A gain of 7 dBi improvement has been achieved. The proposed design process is done with two different solvers, ADS and HFSS.