# Implications of Metamaterial on Ultra-Wide Band Microstrip Antenna Performance
## 1 Introduction
Etching SRR on the ground plane of a microstrip antenna is used to modify antenna's performance. An SRR has been used extensively by many studies in the fields of antenna and microwave devices design. In many applications SRR has been introduced to enhance the performance of the device or suppress the device functionality at specific frequencies. In ([PERSON] et al., 2011), [PERSON] et al. introduced a microstrip antenna with a modified triangular patch, and two arrays of 2 \(\times\) 4 square SRRs were placed on the radiating patch and ground plane. Their proposed antenna has a bandwidth from 3.1 GHz to 9 GHz, and gain increased more than 3 dBi. Research by [PERSON] et al. studied the UWB microstrip patch antenna with metamaterials of X-shaped slots on the radiating patch and ground plane, their design enhanced antenna's bandwidth to cover the range 3.2 GHz to 23.9 GHz, with a peak gain of 6.2 dB ([PERSON] et al., 2011). [PERSON] et al. (2011) designed the UWB antenna with a hexagonal split-ring resonator (HSRR) for sensing the PH factor in sensor application. The designed antenna covers the bandwidth between 3 GHz to 20 GHz and total antenna efficiency of 70% with a gain of 3.88 dB. [PERSON] et al. (2011) proposed a UWB monopole antenna covering a frequency band from 3.1 GHz to 10.6 GHz with a notched band that occurs around 5 GHz to 6 GHz. This antenna operates for wireless local area networks (WLAN) due to SRR on the ground plane. In ([PERSON] et al., 2011), UWB circular monopole antenna was studied, the antenna covers the entire UWB bandwidth 3.1 GHz to 10.6 GHz. Two rectangular shaped SRR were implemented to create a notched band between 6.41 GHz to 8.26 GHz for X-band satellite communication application. [PERSON] et al. (2013), have used an array of a complimentary double-ring SRR on the conducting backplane of a square patch antenna with a single resonance frequency at 3.5 GHz. Their proposed design has resulted in a 22% size reduction, where as other antenna parameters, such as directivity and maximum gain were not affected by the introduction of the SRR. In another application [PERSON] and [PERSON] [PERSON] and [PERSON] (2014) designed a fidget spinner-shaped antenna with four operating bands. Then the authors introduced a double circular SRR on the antenna side. The authors concluded that the introduction of the SRR helped to improve the impedance matching of antenna, which resulted in an improved reflection loss at the original operating band without the SRR. [PERSON] et al. (2015) implemented an artificial magnetic conductor surface with meander monopole antenna to improve antenna's electromagnetic performances. This study investigates how different shapes and configurations of an SRR, mainly circular SRR (C-SRR) and square SRR (S-SRR) will alter the performance of an UWB circular microstrip antenna. The circular microstrip patch antenna and SRRS arrangements are simulated and assessed by ANSOFT's high-frequency structure simulator (HFSS V18). Measurements of selected designs that are fabricatedin UAEU labs will be discussed. It is expected that SRR will increase antenna's bandwidth and provides the possibility to transmit or reject specific frequencies bands based on SRR design parameters.