Compact mobile communication antennas

The launch of new mobile satellite communication links for telephone and data applications demands development of small, low-profile, low-cost antennas. Examples include Teledesic operating at 19 and 29 GHz and Globalstar at 1.6 GHz and 2.5 GHz. The bandwidths are not demanding but the band spacings provide a challenge to the antenna engineer. Microstrip patch antennas are obvious candidates as antennas for these applications. Dual banding techniques for patch antennas have often focused around stacked patch designs where each patch radiates at a different frequency. This paper describes two novel microstrip patch antennas which fulfil this role. The first is a slot patch design which operates at with a frequency spacing ratio of 1.5 which presents particular difficulties in terms of suppressing unwanted mode excitation. The second a dual semi-ring patch demonstrated for the Iridium band as an example application