A Monolithic AlGaN/GaN HEMT VCO Using BST Thin-Film Varactor

Author

Kong, Cen ; Li, Hui ; Chen, Xiaojian ; Jiang, Shuwen ; Zhou, Jianjun ; Chen, Chen

Author_Institution

Sci. & Technol. on Monolithic Integrated Circuits & Modules Lab., Nanjing Electron. Devices Inst., Nanjing, China

Volume

60

Issue

11

fYear

2012

Firstpage

3413

Lastpage

3419

Abstract

A monolithic AlGaN/GaN HEMT voltage-controlled oscillator (VCO) using a barium-strontium-titanate (BST) thin-film varactor is presented. The fabrication process of the VCO is fully compatible with the standard process of GaN HEMT monolithic microwave integrated circuits (MMICs). An improved equivalent circuit model of the fabricated BST varactor for microwave application was developed for the MMIC VCO circuit design. The experiment MMIC VCO exhibits 1-GHz tunable bandwidth at the central frequency of 7 GHz when the BST varactor bias changed from 0 to 24 V. An output power of 17 dBm and phase noise of -81 dBc/Hz (at offset of 100 kHz) are obtained at drain bias of 8 V and BST varactor of 0 V. The results indicate that the monolithic BST varactor is suitable for microwave application, and the integration of the BST varactor can be successfully applied to develop various tunable GaN MMICs.

Keywords

HEMT integrated circuits; III-V semiconductors; MMIC oscillators; aluminium compounds; barium compounds; equivalent circuits; gallium compounds; strontium compounds; thin film capacitors; varactors; voltage-controlled oscillators; wide band gap semiconductors; AlGaN-GaN; BST thin-film varactor; BaSrTiO₃; MMIC VCO circuit design; VCO fabrication process; bandwidth 1 GHz; barium-strontium-titanate thin-film varactor; equivalent circuit model; frequency 7 GHz; microwave application; monolithic BST varactor; monolithic HEMT VCO; monolithic HEMT voltage-controlled oscillator; monolithic microwave integrated circuits; phase noise; voltage 0 V to 24 V; Gallium nitride; HEMTs; Integrated circuit modeling; MMICs; Tuning; Varactors; Voltage-controlled oscillators; AlGaN/GaN HEMT; barium–strontium–titanate (BST) varactor; monolithic microwave integrated circuit (MMIC) process; monolithic voltage-controlled oscillator (VCO);

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2012.2209442

Filename

6266715