Designing a Frequency Multiplier Based on Conventional X-Parameters

This work demonstrates a straightforward analytical helpful technique to determine the transistor’s input and output reflection coefficients to achieve the maximum conversion gain (CG) of RF frequency multiplier (FM) circuits using conventional
$X$
-parameters (
$Z_{L}$
=
$50 \Omega $
) of a transistor. Two frequency doubler (FD) circuits, one at 2.4 GHz and the other having 400 MHz of bandwidth (1.6–2.0 GHz), were designed and fabricated using a GaAs FET ATF38143. The experimental data show a maximum difference of 0.5 dB between the measured and theoretical data of the CG. These results demonstrate the strength of the proposed technique to design FD circuits using the conventional
$X$
-parameters of an FET.