There are three power transistor which have been widely used in s band now : bipolar junction transistor ( bjt ) , gaas metal - oxide semiconductor field effect transistor ( gaas mosfet ) and lateral diffuse metal - oxide semiconductor field effect transistor ( ldmos fet ) . thanks to the advantages , such as , wide frequency , easy power supply , good stability , the ldmos fet has used in the motion telecommunication 目前在s波段人們常用的放大器有雙極性晶體管( bjt ) 、砷化鎵場效應(yīng)晶體管( gaasmosfet ) 、邊緣擴散場效應(yīng)晶體管( ldmosfet )等,由于ldmosfet具有頻帶寬、供電方便、穩(wěn)定可靠等優(yōu)勢,目前已經(jīng)廣泛用于移動通信3g的研究。