مرکز منطقه ای اطلاع رساني علوم و فناوري - A Low Phase-Noise <formula> <img src="/images/tex/380.gif" alt="X"> </formula>-Band MMIC VCO Using High-Linearity and Low-Noise Composite-Channel <formula formulatype="inline"> <img src="/images/tex/555.gif" alt="{\\hbox {Al}}_{0.3}{\\hbox {Ga}}

Title :

A Low Phase-Noise $X$ -Band MMIC VCO Using High-Linearity and Low-Noise Composite-Channel ${\\hbox {Al}}_{0.3}{\\hbox {Ga}}_{0.7}{\\h</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Author : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>Cheng, Zhiqun Q. ; Cai, Yong ; Liu, Jie ; Zhou, Yugang ; Lau, Kei May ; Chen, Kevin J.</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Author_Institution : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>Dept. of Electron. & Comput. Eng., Hong Kong Univ. of Sci. & Technol.</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Volume : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>55</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Issue : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>1</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>fYear : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>2007</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Firstpage : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>23</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Lastpage : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>29</div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Abstract : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>A low phase-noise X-band monolithic-microwave integrated-circuit voltage-controlled oscillator (VCO) based on a novel high-linearity and low-noise composite-channel Al<sub>0.3</sub>Ga<sub>0.7</sub>N/Al<sub>0.05</sub>Ga<sub>0.95 </sub>N/GaN high electron mobility transistor (HEMT) is presented. The HEMT has a 1 mumtimes100 mum gate. A planar inter-digitated metal-semiconductor-metal varactor is used to tune the VCO´s frequency. The polyimide dielectric layer is inserted between a metal and GaN buffer to improve the Q factor of spiral inductors. The VCO exhibits a frequency tuning range from 9.11 to 9.55 GHz with the varactor´s voltage from 4 to 6 V, an average output power of 3.3 dBm, and an average efficiency of 7% at a gate bias of -3 V and a drain bias of 5 V. The measured phase noise is -82 dBc/Hz and -110 dBc/Hz at offsets of 100 kHz and 1 MHz at a varactor´s voltage (V<sub>tune</sub>)=5 V. The phase noise is the lowest reported thus far in VCOs made of GaN-based HEMTs. In addition, the VCO also exhibits the minimum second harmonic suppression of 47 dBc. The chip size is 1.2times1.05 mm<sup>2</sup></div> </div> <div class='row'> <div class='leftDiv labelDiv col-xs-4 col-sm-2 fullRecLabelEnglish'>Keywords : </div><div class='valueDiv leftDirection leftAlign col-xs-8 col-sm-10 fullRecValueEnglish'>III-V semiconductors; MMIC oscillators; Q-factor; aluminium compounds; gallium compounds; high electron mobility transistors; varactors; voltage-controlled oscillators; 4 to 6 V; 9.11 to 9.55 GHz; Al<sub>0.3</sub>Ga<sub>0.7</sub>N-Al<sub>0.05</sub>GaN<sub>0.95 </sub>N-GaN; HEMT; MMIC VCO; Q factor; X-band VCO; harmonic suppression; high electron mobility transistor; high-linearity composite-channel; interdigitated metal-semiconductor-metal varactor; low phase-noise VCO; low-noise composite-channel; monolithic-microwave integrated-circuit voltage-controlled oscillator; planar metal-semiconductor-metal varactor; polyimide dielectric layer; spiral inductors; Dielectrics; Frequency; Gallium nitride; HEMTs; MODFETs; Phase noise; Polyimides; Varactors; Voltage; Voltage-controlled oscillators; <formula formulatype=$ ${hbox{Al}}_{0.3}{hbox{Ga}}_{0.7}{hbox{N/Al}}_{0.05}{hbox{Ga}}_{0.95}{hbox{N/GaN}}$ high electron mobility transistor (HEMT); monolithic; phase noise; voltage-controlled oscillator (VCO);