Low-power variable impedance load/tuning unit

An impedance tuner is presented which operates over the range 1.8 to 3 GHz. The tuner is suitable for use as either a one-port variable impedance termination or as a two-port tuning element. It employs a broadside coupler and a varactor diode tuned phase shifter and can yield vertical bar Gamma MAX vertical bar of nearly 0.9 giving near total coverage of the Smith chart. The power consumption of the whole unit is less than 800 mW, making it suitable for low-power applications. The size of the unit is 23 x 5 mm. Representative tuning and rejection variation are given for 2.2 GHz operation.