New coplanar GaAs P-HEMT matrix distributed amplifier IC with 250 GHz gain-bandwidth product

This paper proposes a new matrix distributed amplifier design technique, named, shifted second tier. In the conventional matrix distributed amplifier, amplifications from the earlier nodes of the center line are small and contribute little to the output because the node voltages are the sum of forward and reverse propagating waves, which are out of phase with each other. Therefore, by shifting the second tier to the output load, amplifications from the earlier center line nodes are suppressed while those from the later ones are increased, which results in a gain enhancement without a bandwidth reduction. The proposed design has been verified by using recently developed, high-yield 0.25-μm non-recessed self-aligned gate GaAs P-HEMT coplanar MMIC technology. From the measurement, the newly designed IC has a gain of 18.5 dB from DC to 30 GHz, which is about 3 dB higher than that of the conventional circuit. To our knowledge, the obtained gain-bandwidth product (250 GHz) is the best result ever reported for monolithic GaAs IC's.