Surface Micromachined Millimeter-Wave Log-Periodic Dipole Array Antennas

Two wideband millimeter-wave end-fire log-periodic dipole array (LPDA) antennas are designed and fabricated using a sequential surface micromachining. The antennas are excited by monolithically integrating a micro-coaxial line feed in the antenna´s lower boom designed to provide band rejection at 60 GHz. Antennas 1 and 2 are designed to operate in 18-110 GHz and 18 GHz-50 GHz bands, and measured up to 40 GHz and 50 GHz, respectively. VSWR <; 2.5 is obtained for both antennas throughout the measured bandwidth. Measured directivity around 10 dBi and consistent E and H-plane 3 dB beamwidths around 56^° and 72^°, respectively, are obtained for Antenna 2 throughout its bandwidth. Good pattern correlation between measured and simulated results is also achieved. This paper clearly demonstrates that the wideband high-quality millimeter-wave end-fire LPDAs are now possible.