Abstract:
A design method for broadband reflective linearizer with specific gain and phase compensation is proposed, and a predistortion linearizer for solid-state power amplifiers is designed by this method. Nonlinear compensation is produced using the Schottky diode. The MATLAB optimization tool is utilized to calculate the shunt load’s impedance at a single frequency point with the specified gain and phase compensation in accordance with the circuit topology. To obtain the variation of the shunt load with frequency necessary for a specific gain and phase compensation, i.e. the
ZL-
f curve, the frequency point is changed, and the aforementioned procedures are repeated. The circuit is optimized using the ADS software so that the change in impedance of the diode's parallel load with frequency is approximated by the
ZL-
f curve. The gain compensation and phase compensation of the circuit simulated in this paper are 6 dB and −40°, respectively. The final measurement reveals that the frequency band characteristics are good when the frequency range is 9.4–11.4 GHz, the gain expansion is 3.9–4.4 dB, and the phase compensation is −32.3°–41.5°. Additionally, the relative bandwidth of linearizer is 19.2%. By changing the DC bias voltage of the diode, the slope of the compensation curve is also adjustable.