Frequency Selective Degeneration for 6–18 GHz GaAs pHEMT Broadband Power Amplifier Integrated Circuit

Abstract

In this paper, a frequency selective degeneration technique using a parallel network with a resistor and capacitor is proposed for a 6–18 GHz GaAs pseudomorphic high electron mobility transistor (pHEMT) broadband power amplifier integrated circuit (PAIC). The proposed degeneration network is applied to the source of the transistor to flatten the frequency response of the transistor in conjunction with feedback and resistor biasing circuits. An almost uniform frequency response was achieved at the wide frequency band through optimizing the values of the capacitor and resistor for the degeneration circuit. Single-section matching networks for small chip sizes were adopted for the two-stage amplifier following the flat frequency characteristics of the degenerated transistor. The proposed broadband PAIC for the 6 to 18 GHz band was fabricated using a 0.15 μm GaAs pHEMT process and had a chip size of 1.03 × 0.87 mm2. The PAIC exhibited gain of 15 dB to 17.2 dB, output power of 20.5 dBm to 22.1 dBm, and linear output power of 11.9 dBm to 13.45 dBm, which satisfies the IMD3 of −30 dBc in the 6–18 GHz band. Flatness for the gain and output power was achieved as ±1.1 dB and ±0.8 dB, respectively.

2–26.5 GHz GaN ultra‐wideband amplifier with over 2 W output power

“…In recent years, monolithic microwave power amplifiers (PAs) in the frequency band 2 ~18 and 18 ~26.5 GHz have developed rapidly. [1][2][3][4][5][6] However, to cover a broader frequency band like 2-26.5 GHz with high output power, it is still a challenge until now. A.S. Virdee reported a 2-18 GHz PA with an output power of 25 dBm.…”

“…The wide‐band microwave amplifier is widely used in radar electronic countermeasures and microwave measurement systems. In recent years, monolithic microwave power amplifiers (PAs) in the frequency band 2 ~ 18 and 18 ~ 26.5 GHz have developed rapidly 1–6 . However, to cover a broader frequency band like 2–26.5 GHz with high output power, it is still a challenge until now.…”

Design of a Broadband MMIC Driver Amplifier with Enhanced Feedback and Temperature Compensation Technique

“…Many pivotal points in the design of broadband PAs need special attention. Related indicators include gain, power, flatness, input and output reflection coefficients, chip area and linearity [11]. Therefore, it is very challenging to design a broadband drive amplifier that meets actual application requirements.…”

“…Generally speaking, these chips require low return loss, good gain flatness and high broadband output power in a wideband range. In order to achieve these goals, feedback amplifiers, distributed amplifiers, lossy matched amplifiers and balanced amplifiers are widely used [11][12][13][14][15]. Feedback amplifiers establish a feedback loop between the input and output, feed back a part of the output signal to the input and realize bandwidth expansion by sacrificing part of the low-frequency gain.…”

“…At the same time, they can adjust the input and output impedance. Therefore, it is easier to obtain broadband matching performance [11]. Distributed amplifiers rely on the parameters of transistors to absorb parasitic capacitance into the artificial transmission line, and ultrawideband can be realized [12,15].…”