A Highly Isolated Millimeter-wave Encapsulated Antenna for Radar Sensing

In this paper, a group of millimeter-wave antennas with high isolation are packaged for radar sensing. There are three patch antennas encapsulated in a compact aperture with the dimension of 15×15 mm
²
, where two of them are employed for signal reception and the left one is for signal transmission. Although the two antennas for reception are closely placed, the isolation between them is enhanced to more than 20 dB by introducing an H-shaped decoupling structure. In addition, we design a coplanar waveguide (CPW) transition between the feed probe and connector for the convenience of measurement. For demonstration, the proposed encapsulated millimeter-wave antenna is fabricated and measured. The measured results shows that the common impedance bandwidth (reflection coefficient < - 10 dB) of the three antennas are wider than 1 GHz and the gains are higher than 5 dBi. As a result, the proposed design has a potential for the application in smart home.