2.4 GHz LNA/PA/circularly polarized active microstrip antennas

The design, numerical simulation, realization and measurement of 2.4 GHz amplifier-type circularly polarized (CP) active microstrip, cl,antennas are presented. A lo-to noise amplifier (LNA) is used for the receiving assembly and a power amplifier (PA) is used for the transmitting configuration. A 2.4 GHz CP square-microstrip antenna using a Lange coupler for two orthogonal feeds is designed. The spectral-domain electric field integral equation (SD-EFIE) techniques is employed to accurately determine the microstrip antenna dimensions, input SWR, current distribution ann radiation patterns. The semibalanced amplifiers (using PAs or LNAs) are designed ann integrated with thee,microstrip antenna to form a transmitting- or receiving-type CP active microstrip antenna. The microstrip antenna/amplifier modules are fabricated on two FR-4 substrates with the ground planes soldered together Potential application of the CP active microstrip antennas include base station antennas for industrial, scientific and medical (ISM)-band cordless telephones or wireless local area networks (WLAN).