An ultrabroadband monolithic lossy match power amplifier using prematching circuits

Abstract

This paper describes the design, fabrication, and performance of wideband monolithic lossy match power amplifiers employing prematching circuits, which make the frequencydependence of input and output impedance of FETs small. First, it is shown theoretically that a wide bandwidth can be achieved by using prematching circuits in the design of lossy match power amplifiers. Second, a novel constant-resistance network and a parallel resonant circuit are proposed as prematching circuits. Impedance matching methods using prematching circuits are also described. Finally, by employing these prematching circuits in the design and fabrication of a C -K bandpower amplifier, it is experimentally shown that the impedance matching methods using prematching circuits are useful in the design of wideband lossy match power amplifiers. The amplifier exhibits a linear gain of 10 f 2.3 dB, a saturated power of 28.3 f 1 dBm, and a drain efficiency of 12.6 f 2.2 percent over 5 -21 GHz. These measured performances are in good agreement with the calculated results. The prematching circuits, which make the frequencydependence of input and output impedance of FETs small, are useful for achieving a wide bandwidth of lossy match power amplifiers. In addition, the parallel resonant circuit, which comprises only reactive elements, is also useful in the design of output matching circuits for achieving high gain and high power.

1W power amplifier MMICs for mm-wave applications

“…The input, inter-stage and output matching circuits are composed of pre-matching circuits and impedance transformers. As pre-matching circuits which make the frequency-dependence of input and output impedance of FETs small, a constant resistance network is employed for the input side of the FET, and a parallel resonant stub is employed for the output side of the E T [7]. As impedance transformer, Chebyshev low-pass filter configuration is employed [8].…”