A Compact Ultra-Wideband Chip Antenna with Bandwidth Extension Patch and Simple Isolator for MIMO Systems for Mobile Handheld Terminals

A compact ultra-wideband (UVVB) chip antenna that has high isolation for multi-input multi-output (MIMO) systems is presented in this paper. The antenna is composed of a chip antenna, a printed circuit board, and an isolator stub. High isolation was obtained using a simple stub, and a low-frequency band was extended by applying a bandwidth extension patch to the chip antenna. The pulse performance of the proposed antenna was measured by changing the angle of the receiving antenna. The proposed antenna was simulated by applying a hand phantom. The effect of the grip position of the hand phantom on the reflection coefficient, isolation, and gain was analyzed. The measured impedance bandwidth was 2.45 GHz to 9 GHz. The proposed UWB MIMO antenna has a high isolation, greater than 25 dB, at the operating frequency. The antenna gain varied from 3 dBi to 4.5 dBi over the operating frequency range. The measured group delay variation was less than 1 ns. The measured pulse features have negligible chirp and a small dispersion.