Design of a 94-GHz Single Balanced Mixer Using Planar Schottky Diodes with a Nano-Dot Structure on a GaAs Substrate

In this paper, we develop a 94-㎓ single balanced mixer with low conversion loss using planar Schottky diodes on a GaAs substrate. The GaAs Schottky diode has a nanoscale anode with a T-shaped disk that can yield high cutoff frequency characteristics. The fabricated Schottky diode with an anode diameter of 500 ㎚ has a series resistance of 21 Ω, an ideality factor of 1.32, a junction capacitance of 8.03 fF, and a cutoff frequency of 944 GHz. Based on this technology, a 94-㎓ single balanced mixer was constructed. The fabricated mixer shows an average conversion loss of -7.58 ㏈ at an RF frequency of 92.5 ㎓ to 95 ㎓ and an IF frequency of 500 ㎒ with an LO power of 7 ㏈m. The RF-to-LO isolation characteristics were greater than -32 ㏈. These values are considered to be attributed to superior Schottky diode characteristics.