Microstrip patchantenna is commonly used for wireless communication system because of manyadvantages like low-cost, low-profile and easy fabrication. However, microstrippatch antenna have several disadvantages such as narrow bandwidth and low gain.The incresing growth of wireless system needs miniaturized antenna. The size ofantenna must be reduced due to the development of technologies wireless systemsbecoming more compact. There are several miniaturization techniques to reducesize of antenna. One of the techniques is by usinghigh permittivity material. The wave propagation will increase within thesubstrates and radiation effeciency is lower due to losses are increasing andalso decrement of bandwidth. A lot of different materials have been use tominiaturize the antenna.
In (H. M. Chen, Y. K. Wang, Y. F.
Lin, C. Y. Lin and S. C. Pan, April 2009), the ceramicsubstrate is used in square ring microstrip patch antenna with dielectricconstant of 58. Circular polarization was achieved by simple microstrip feedline through coupling on the same plane. 50% of size reduction was achievedwith 1.1% of impedance bandwidth at 1.
573 GHz. By using magneto-dielectricsubstrate for miniaturization of microstrip patch antenna, 65% of sizereduction was achieved at 2.45 GHz (P. M. T. Ikonen, K. N. Rozanov, A.
V. Osipov, P. Alitalo and S.
A. Tretyakov, Nov. 2006).
The most commonly technique tominiaturize antenna is slots on the patch. Various slots with different lengthswere used in (S. I. Hussain Shah, S. Bashir and A. Altaf, 2014) on the patch antenna such as U and Lshaped slots. By using shorting pin, the patch and ground plane were shortedcausing an increment of electrical path length for current flow and 86% of sizereduction.
The antenna is operated at multiple bands of frequencies and gain atthe frequency range is 3.5 dBi to 6.6 dBi. A single layer microstrip patchantenna on FR4 substrate is designed in (Kamboj, V., Saini, G.
, and Saini, A., July 2016)using etching polygon, rectangular and square shaped slots to miniaturize andimprove the bandwidth. The antenna is operate in S-band and the size of antennahave bee reduced to 37.
8% with 260 MHz of impedance bandwidth and 2.36 dB ofgain. A patch antenna was designed usingmetamaterial in (T. K. Upadhyaya, V. V. Dwivedi, S.
P. Kosta and Y. P.
Kosta, 2012) for low frequencydomain for dual transmit and single receive frequency. The combination of split-ring resonator (SRR)and thin wires (TW) which is made up of copper is used as substrate of patchantenna for generation of artificial composite material. FR4 is used asdieletric substrate material. The performance of antenna showed -20 dB returnloss was achieved with 80% of size reduction. An AMC structure is used on amicrostrip patch antenna where AMC act as a ground plane in (F. Rahmadani and A. Munir, 2011).
The antenna is designed to resonate at 2.45 GHz and it is deployed on FR-4substrate. The proposed antenna has 100 MHz of bandwidth with return loss of12.8 dB and 1.53 of gain.
The size of the antenna is reduce more than 31% withincorporation of AMC structure. Table 2.1 showed the summary of miniaturizationtechniques microstrip patch antenna.