Directivity‐enhanced Planar Slot Antenna Backed by Substrate Integrated Waveguide Cavity

In this paper, a directivity-enhanced planar slot antenna (PSA) backed by substrate integrated waveguide (SIW) cavity is proposed to solve the problem of maximum gain direction bias. According to the radiation principle of slot antenna, the reason for maximum gain direction bias is explained and the solution has been given. Ulteriorly, the problem of frequency bias caused by changing the directivity is also explained by resonance modes and solved by introducing the metal via. An example with 5.8 GHz which has the maximum gain of 5.28 dBi and the total thickness less than lambda/4 is given. After structural optimization and measurement, the maximum radiation direction of improved antenna is 0 degrees from the normal direction of antenna surface, and it maintains the good radiation performance and small size of the traditional PSA backed by SIW cavity.