Dual-band GPS antennas with single-feed and low-profile configurations

The authors developed two types of multi-band GPS antennas with a single feed point and low profile configuration, that is, one is the slot typed antenna and the other is the micro-strip typed antenna. Here the targeted characteristics in both bands are a return loss of less than-10dB, an axial ratio of less than 3dB. Aiming at GPS services, one frequency band at L1 band (with a center frequency of 1.57542 GHz) is presently assigned. Still more in the near future, L2 band (with a center frequency of 1.2276 GHz) will be added so that two-frequency operation will be initiated.