A large planar 39-GHz antenna array of waveguide-fed horns

A planar antenna in which box horns are used as radiating elements is described. The feed network is built by connecting rectangular waveguides with T-junctions. The matching of the T-junctions is improved by using rounded splitters and matching pins in the junctions. The radiating element has been designed to cancel out the grating lobe. The grating lobe is due to an element spacing larger than one wavelength. The highest sidelobes are at least 31 dB below the main beam in the H-plane and 16 dB in the E-plane. A gain of 37 dBi has been achieved at 39.2 GHz. These results demonstrate the feasibility of this antenna for applications requiring high gain at millimeter wavelengths     

A high-gain 58-GHz box-horn array antenna with suppressed gratinglobes

A low-profile high-gain antenna array of box horns for the frequency band 57.2-58.2 GHz is presented. The antenna consists of 256 radiating elements divided into two subgroups of 128 elements fed by a rectangular waveguide feed network. The radiating elements are fed in parallel and the waveguides are connected with T-junctions. The matching of the T-junctions is improved with a matching pin and a splitter. Because of the waveguide feed network, the element spacing is larger than one wavelength, which causes grating lobes. The grating lobes and sidelobes in the H-plane have been suppressed by the use of a combination of subarrays, a special characteristic of the box horn, and an array amplitude tapering. The measured sidelobe levels in the H-plane are below -30 dB at angles larger than 8° from boresight. A gain higher than 35.7 dBi and a return loss higher than 14.4 dB have been measured for the antenna over the band 57.2-58.2 GHz     

Antenna measurements using a hologram CATR

It becomes increasingly difficult to obtain far-field measurements for large millimetre wave antennas at higher frequencies due to the required large distance between the antennas. A hologram compact antenna test range (CATR) is used to determine the radiation characteristics of a 39 GHz planar antenna in a small facility. The results are compared with those obtained from planar near-field scanning and conventional far-field measurements     

Planar 64 element millimetre wave antenna

A simple 64 element planar array antenna, with H-plane sidelobes below -35 dB at larger angles than 19° from boresight and a gain above 30.4 dBi, is presented for the band 37.0-39.5 GHz. The radiating elements are fed in parallel by a waveguide feed network. The H-plane sidelobe level is reduced by using a combination of arrays, the zero in the element radiation pattern, and amplitude tapering