A multiplier-type microwave FET mixer

Abstract

Generally the nonlinearity of a semiconductor diode or transistor is utilized for mixing operation. In that type of mixer the two input signals are combined to one port while the output can be filtered from the other port. This requires high local oscillator power and higher order sideband signals are also generated. This paper presents a multiplier-type microwave FET mixer which does not exhibit the mentioned problems. In a multiplier-type mixer there are two or three ports and the two input signals are applied to different ports. We designed and realized a mixer with its filters in a microstrip structure and verified its functionality by simulations and measurements. The mixer operates at 2GHz, however, the design methods may be used for higher frequencies as well. The presented work gives way to develop a similar tunable circuit suitable for use in a software-defined radio network such as the 5G system.