Heterodyne analysis of metal-oxide-metal diodes

The heterodyne analysis of a metal-oxide-metal (MOM) diode is presented. The analysis is based upon the equivalent circuit and antenna models of the MOM diode. Expressions are derived for the noise equivalent power per Hz (NEP/Hz) for two sources of limiting noise. The first noise limitation considered is shot noise of the current in the diode due to a dc bias voltage of ∼0.2 V. The second noise considered is the shot noise associated with local oscillator (LO) induced current. For a temperature of 300 °K and circuit parameters chosen to optimize the tunnel diode operation, the theoretically ideal NEP/Hz is estimated for the LO and bias voltage noise to be 2×10−18 and 6.7×10−17, respectively.