Design concept of compact multilayer ultra-wideband antipodal slot antenna

In this paper, design concept of multilayer, compact antipodal slot antenna with high performance is presented. The sandwich feed line is connected to two feed pads printed on both sides of a substrate by a metallic via so that the coaxial-cable connector or other components can be directly connected to the antenna. The new antenna's impedance bandwidth is from 3.12GHz to 10.8GHz, which is about 3.4:1. Stable omnidirectional radiation patterns with low cross-polarization level, gain flatness of less than 3dB over the frequency range are also obtained.