Miniaturization of Microstrip Antenna by CRLH-TL Technique

Abstract

In this paper, an electrically small microstrip antenna has been presented by employing composite right/left-handed transmission line. The prototype antenna was designed by using Interdigital capacitor and spiral inductor. It is fabricated and printed on FR-4 low cost substrate with dielectric constant 4.4 and thickness 1.6 mm, Dimensions of antenna are $$15.5\,\hbox {mm}\times 12\,\hbox {mm}$$15.5mm×12mm. So, the size reduces about 69 % compared with conventional microstrip patch antennas at 1.8 GHz and more than 80 % for 1.1 GHz. Final model of the antenna has triple bands at 1,060, 1,800 and 2,500 MHz. Which two frequencies (1.8 and 2.5 GHz) are suitable for GMS and WLAN applications. The presented antenna is simulated in HFSS, Finally the simulated and experimental results are compared. The antenna has low gain so, it is suitable only for indoor and medical care applications which we need low power and low profile devices. The maximum gain of antenna at 2.4 GHz is around $$-$$-8 dBi that it is drawback of antenna, but it will sufficient for indoor and implant application such as health care. The antenna has an Omni directional pattern and a linear polarization.