Off-Chip Double U-Shaped Slot Patch Antenna for H-Band Applications

An innovative planar single layer off-chip antenna for the use in broadband communication and sensing applications in the 220 GHz to 330 GHz frequency range is presented. The antenna employs the use of double U-shaped slots as loading for a rectangular patch to introduce coupled resonances, leading to a broadband radiation characteristic. As an off-chip design, low permittivity substrates, such as fused silica, can be used, ensuring good radiation characteristics. An impedance transformer is added to the microstrip antenna feed line allowing to match a 50 ohm bondwire connection to the 65 ohm antenna input impedance, satisfying the condition of a reflection coefficient of less than −10 dB over the whole desired frequency range. Simulation and measurement show good accordance, with the antenna having a peak gain of 6.2 dBi at the centre frequency of 300 GHz, only 0.4 dB less than the simulated value. In the measurements a bandwidth of at least 13.3 % is achieved, more than four times the bandwidth of a standard rectangular patch antenna on the same substrate.