Dual-Frequency Matching Technique and Its Application to an Octave-Band (30-60 GHz) MMIC Amplifier


IEICE TRANSACTIONS on Electronics   Vol.E80-C       pp.1614-1621
Publication Date: 1997/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Category: Microwave and Millimeter Wave Technology
MMIC,  amplifier,  broad-band,  impedance matching,  quarter-wavelength,  

Full Text: PDF>>
Buy this Article

A single-stage dual-frequency matching network that can simultaneously transform a transistor reflection coefficient to zero at two separate frequencies (a lower frequency fL and a higher frequency fH) is proposed. The network is made by adding a shorted stub, the length of which is a quarter-wavelength at fH, to a conventional L-section matching network composed of a series transmission line and an open stub. The concept of dual-frequency matching is based on the fact that the synthesized shunt admittance of the open and shorted stubs changes from capacitive at fH to inductive at fL. By means of the single-stage matching network, broad-band amplifier performance, the bandwidth of which is given as (fH-fL), can be easily obtained with almost the same design procedures and circuit area used for conventional narrow-band amplifiers. In this paper, the function of the dual-frequency matching network is analyzed in detail and an application of the matching technique to a two-stage amplifier is described. A broad-band performance of |S21|>7.4 dB at 27.0-62.5 GHz has been achieved with a GaAs P-HEMT two-stage MMIC amplifier.