A ROTATING MODE RADIAL LINE SLOT ANTENNA FED BY A CAVITY RESONATOR

A radial line slot antenna (RLSA) is a high gain and high efficiency p lanar antenna proposed for DBS subscribers. Spirally arrayed slots are excited by a cylindrical wave with the rotational symmetry. In a smal l sized antenna where large slot coupling is adopted, aperture efficie ncy reduction due to rotational asymmetry associated with a spiral arr angement of the slots becomes notable. Authors proposed a RLSA with a concentric slot arrangement excited by a rotating mode in order to enh ance the rotational symmetry. This is the first report of the normal o peration of a rotating mode RLSA fed by a cavity resonator. The experi ments confirm the basic operation of this novel antenna; the gain of 2 7.8 dBi and the efficiency of 68% is measured at 11.85 GHz for the RLS A with 0.24 m phi.