Low cost modular integrated horn antenna array using heterojunction barrier diode detectors

Heterojunction barrier diode (HBD) detectors are introduced with optimized zero bias and room temperature performance at millimeter wave frequencies. Through careful device development and fabrication techniques they have been scaled successfully to micron size values and exhibit high dc responsivity of 17 A/W at zero bias with a low capacitance of 1.5 fF/um
²
. At 100 GHz they have been shown to have rf responsivities of 23000 V/W, recording the highest value to date. An optimized antenna cavity, called an integrated horn antenna, has been designed and has shown to provide improved impedance matching to the HBD detector. A 1×8 integrated horn array has been built using the most cost effective methods which is readily scalable in X and Y dimensions. Following the assembly of the array the antenna pattern and the noise equivalent delta temperature (NEDT) were measured. The lowest room temperature NEDT of 2.47 K has been measured for a direct detector at 30 Hz refresh rate showing an outstanding sensitivity to the millimeter wave radiation.