Indian Journal of Pure & Applied Physics Vol. 51, November 2013, pp. 800-807 Compact microstrip patch antenna for microwave communication Samiran Chatterjee #1 , Santosh Kumar Chowdhury #2 , Partha Pratim Sarkar* 3 , Debasree Chanda Sarkar* 4 #1 ECE Department, West Bengal University of Technology, RCC Institute of Information Technology, Beliaghata, West Bengal, India * 3,4 USIC Department, University of Kalyani, Nadia, West Bengal, India #2 ECE Department, West Bengal University of Technology, JIS College of Engineering, Phase-III, Block-A5, Kalyani, Nadia, West Bengal, India E-mail: 1 samiranengineer@gmail.com; 2 santoshkumarchowdhury@gmail.com; 3 parthabe91@yahoo.co.in; 4 dsarkar70@gmail.com Received 6 January 2013; revised 18 April 2013; accepted 30 August 2013 A single layer, single feed compact rectangular microstrip antenna is proposed. Resonant frequency has been reduced drastically by cutting three unequal rectangular slots at the edge of the patch and also small rectangular slots connected with the middle of every patch. Antenna size has been reduced by 47.4% with an increased frequency ratio when compared to a conventional square microstrip patch antenna. Keywords: Compact Patch, Slot antenna, Microwave resonant frequency patch antenna 1 Introduction In recent years demand for small antennas in wireless communication has increased the interest of research work on compact microstrip antenna design among microwaves and wireless engineers 1 . To support the high mobility necessary for a wireless telecommunication device, a small and light weight antenna is likely to be preferred. For this purpose, Compact Microstrip antenna is one of the most suitable devices. The development of antenna for wireless communication also requires an antenna with more than one operating frequency. This is mainly because there are various wireless communication systems and many telecommunication operators are using various frequencies. Therefore, one antenna that has multiband characteristic is more desirable than having one antenna for each frequency band. To reduce the size of the antenna one of the effective techniques is cutting slot in proper position on the microstrip patch 2-5 . There are so many antennas which are used to reduce the size of the antenna. Reducing the size of the antenna means the resonant frequency of slotted antenna is drastically reduced as compared to conventional antenna 6-8 .Other than slotted antenna, there are antennas like DRA (Dielectric Resonator Antenna), Fractal Antenna 15-20 etc. Fractal antennas are difficult to design and DRA requires high dielectric constant substrates which are not readily available. Compact microstrip antenna is a topic of intensive research in recent years because of increasing demand for small antennas used in various types of communications including mobile communication 9,10 . The size of the antenna may be effectively reduced by cutting rectangular slots on printed antennas. The work to be presented in this paper is also a compact printed antenna obtained by cutting rectangular slots which gave a resonant frequency much lower than the resonant frequency of the conventional printed antenna with the same patch area. It also increase the return loss and gain- bandwidth performance of the antenna. To reduce the size of the antenna substrates are chosen with higher value of dielectric constant 11-14 . The antennas can withstand exposure to high temperatures when covered by a radome made of the same soft dielectric as the substrate. The cover protects the metal patches but has only a minor effect on the resonant frequency 21 . High temperatures on the surface of the radome or ablation fail to change the resonance significantly because the radome itself has only a minor effect. Variation in the dielectric constant of the substrate from lot-to-lot causes problems with repeatability. The narrowband antennas require measurement of the dielectric constant of each lot, and sometimes of each sheet, to get the center frequency desired. A series of etching masks can be made to cover the expected range. The antennas can be tuned with inductive shorting pins or capacitive