Mutual coupling reduction of low-profile monopole antennas on high-impedance ground plane

The mutual coupling effects of flush-mounted (horizontal) monopole antennas on high-impedance ground planes (HIP) have been measured. Experiments of horizontal monopoles on HIP with a bandgap centred at 4.7 GHz show that the interference between two adjacent elements is stronger compared to those on a regular metal ground plane due to special properties of HIP. A technique using a combination of HIP and thin metal strip is proven to reduce the mutual coupling by /spl sim/6 dB. Similar results have been obtained for the horizontal monopoles on HIP with a bandgap centre at 17 GHz.