了解RF巴倫及其轉(zhuǎn)化功能

　　了解RF巴倫及其轉(zhuǎn)化功能

　　巴倫（收縮平衡-不平衡）一二端口組件放置在電源與負載之間的差分平衡時，射頻功能塊必須連接到一個單一的結(jié)束，地面參考一。雖然它經(jīng)常被“掩蓋”的討論，因為它沒有射頻RF信號鏈增加明顯的價值，這在通常情況下的被動元件是必不可少的。

　　例如，需要一個單端功率放大器（PA）驅(qū)動偶極天線元件（平衡負載）或一個鞭天線（單端）饋送差動前端放大器。你可能熟悉的大眾市場，低成本的巴倫用來連接一個屋頂，空中300Ω偶極子天線的廣播電視到75Ω同軸電纜，然后連接到電視機本身（一些老電視假定偶極天線位于電視，所以只有一雙300Ω，平衡螺絲端子輸入，在這種情況下，一個平衡-不平衡將需要從同軸電纜電視輸入使反變換）

　　However， the need for baluns extends beyond TVs and their antennas： in recent years， RF ICs are increasingly using differential configurations for their internal topology， because this provides improved noise immunity and better overall RF performance， and at a very-low-cost increment due to the nature of IC designs.

　　Baluns are not new or even relatively recent components. They have been used since the earliest days of wireless telephony to resolve the single-ended/balanced dilemma. Now， the growth in portable， handheld， and IoT applications means there is enormous demand for tiny， relatively low-power baluns. These can be constructed using ceramic-based fabrication similar to that used for bandpass filters， directional couplers， and SAW-type oscillators.