Transformer-Feedback Dual-Band Neutralization Technique

Abstract

A dual-band neutralization technique based on transformer feedback between the drain and gate of transistor is presented. The drain and gate bias lines of the transistor are realized as multi-order LC networks. Transformer coupling between inductors of the two networks can be used to concurrently neutralize the gate-drain capacitance of the transistor at multiple frequencies. Moreover, these frequencies can be placed close together to achieve wideband neutralization. A proof-of-concept dual-band 27/33-GHz amplifier is designed and implemented in a 0.1-µm GaAs pHEMT process. The maximum gain of the transistor at the two frequency bands is improved by more than 6 dB using the neutralization technique. The amplifier exhibits gain of 16/15 dB and reverse isolation of 60/50 dB at the lower/upper frequency band. It consumes 24 mA from a 1-V supply.

Ultra-Wideband Transformer Feedback Monolithic Microwave Integrated Circuit Power Amplifier Design on 0.25 μm GaN Process

“…However, these solutions tend to be less efficient and consume larger chip areas. As a better alternative, some research has begun to use onchip transformer feedback in broadband amplifier designs to build feedback matching networks [6][7][8].…”

A novel gain‐boosting structure with Z‐embedding and parallel pre‐embedding network for amplifiers at near‐fmax frequencies

“…To improve the power gain of the amplifier at near-f max frequencies, great efforts have been made to introduce "embedding network" to the active device. [13][14][15][16][17] It has been proven that by properly adopting linear, lossless, and reciprocal embedding network (LLREN), the maximum available gain (G ma ) of an active two-port network (A2P) can be improved while keeping the network unconditionally stable, 18 until G ma gets to the upper limit, which is given as…”

“…It makes the silicon‐based terahertz amplifier without any gain‐boosting techniques exhibit poor power amplification capacity, thus not able to meet the demand of the system requirements. To improve the power gain of the amplifier at near‐ f max frequencies, great efforts have been made to introduce “embedding network” to the active device 13–17 . It has been proven that by properly adopting linear, lossless, and reciprocal embedding network (LLREN), the maximum available gain ( G ma ) of an active two‐port network (A2P) can be improved while keeping the network unconditionally stable, 18 until G ma gets to the upper limit, which is given as , 19,20 where U denotes Mason's U 21 .…”