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RISS 인기검색어
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- 저자 : Jeongkyu Heo (검색결과 1 건)
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Jeongkyu Heo,Jae Choon Kim,Ki Hyuk Kim,Jae-Sung Rieh,Jin Taek Chung,Sung Woo Hwang IEEE 2008 IEEE microwave and wireless components letters Vol.18 No.5
<P>We fabricated and characterized heterojunction field effect transistor radio frequency (RF) power amplifier (PA) test fixtures, for wireless applications, with various printed circuit board (PCB) structures. The RF matching and bias circuits of the test fixtures were designed so that they had the same RF characteristics. The only source of the variation of the RF gain (S<SUB>21</SUB>) was different thermal characteristics of each PCB. The values of the junction temperature (T<SUB>J</SUB>) and the junction-to-ambient thermal resistance (R <SUB>J</SUB> <SUB>A</SUB>) of each test fixture were shown to be changed as much as 80deg C and 30deg C / W, respectively, by the change of PCB structures. The change of Rja was shown to be originated from the change of the PCB thermal resistance, assuring that the structure of the PCB was the dominant factor in determining R <SUB>J</SUB> <SUB>A</SUB> Finally, we obtained a universal relation between S<SUB>21</SUB> of the amplifier and Tj. This work suggests that thermal budget of PCB is as important as that of package in wireless RF equipments.</P>
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