LOW-COST ANTENNAS FOR DIRECT BROADCAST SATELLITE RADIO

Two omnidirectional and circularly polarized low-gain antennas (the cr ossed drooping dipole and the TM21-mode circular patch antenna) are de veloped for direct broadcast satellite radio (DBSR) outdoor mobile ter minal applications. Two medium-gain circularly polarized microstrip pa tch arrays [one uses the conventional circular polarization (CP) feed and the other uses the sequentially arranged CP feed techniques] are a lso developed to provide at least 12-dBic peak gain for DBSR indoor fi xed terminal applications. The sequentially arranged CP fed array has a better CP performance over a broader bandwidth than the conventional ly fed array. All the antennas are small in size/mass and inexpensive in fabrication cost. The patch antennas also have a low profile. (C) 1 994 John Wiley & Sons, Inc.