多帶混合平衡天線

　　小用戶設(shè)備天線的設(shè)計(jì)多年來(lái)一直依賴于非平衡設(shè)計(jì)的使用–通常巧妙的變體的單極和倒L天線。為降低設(shè)備尺寸、非平衡天線成為越來(lái)越嚴(yán)重的問(wèn)題，因?yàn)樗鼈兊妮斎胱杩购洼椛湫阅軓?qiáng)烈依賴于地面和他們的位置在它的大小。

　　本文介紹了一種新的多波段天線采用平衡饋電網(wǎng)絡(luò)顯示從通常的接地面的影響，指出新的天線設(shè)計(jì)方式的實(shí)質(zhì)性免疫，可很少或根本沒(méi)有修改平臺(tái)之間移動(dòng)。為了節(jié)省空間，設(shè)計(jì)包括天線下的一個(gè)海灣，以容納相關(guān)的射頻電路和設(shè)備。

　　Balanced Antennas

　　While an unbalanced antenna has only a single terminal and is driven against the local groundplane， a balanced antenna has two terminals exhibiting equal impedances with respect to the local groundplane. These two terminals are excited with respect to ground by equal voltages with a phase difference of 180°。 This slightly unusual definition makes it clear that there are two ways in which we can imagine a balanced structure （Figure 1b and 1c）。 Figure 1（c） provides a useful insight into an alternative way of realizing a balanced structure by using a complementary pair of unbalanced structures， each of which can use the compressed formats which have become usual in small wireless devices.