Wheel-shaped miniature assembly of circularly polarized wideband microstrip antenna for 5G mmWave terminals

Abstract

A simple arrangement of wheel-shaped copper microstrip antenna is presented for operation in the 24 GHz frequency band. In this structure, a coaxial feed probe was utilized to generate vertical polarization, and a wheel-shaped microstrip with four coupling arms was used to produce horizontal polarization. An antenna comprising of two copper sheets assembled between the air-substrate was manufactured and characterized experimentally. The measured and simulated values are in close compliance with each other. A stable in-band omnidirectional radiation patterns were achieved thereby ensuring a proper combination of the field vectors from the feed probe and the radiating arms. The antenna occupied an overall footprint of 8 mm to fruitfully realize −10 dB impedance bandwidth >3 GHz and radiation efficiency of ~100%. In the operating frequency band from 22.5 to 25.7 GHz, axial ratio <2.7 dB, gain <6 dBic and specific absorption rate (SAR) <0.06 W/kg was maintained. Furthermore, the integration of simple geometry and air-substrate significantly reduced the fabrication cost of the antenna system. Hence, the antenna is a promising candidate for 5G millimeter (mmWave) wireless communications.

Keywords

• 24 GHz band
• 5G wireless technology
• Antenna
• Circular polarization
• mmWave communications
• Wideband