多帶混合平衡天線

　　小用戶設(shè)備天線的設(shè)計多年來一直依賴于非平衡設(shè)計的使用–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越嚴重的問題，因為它們的輸入阻抗和輻射性能強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)計方式的實質(zhì)性免疫，可很少或根本沒有修改平臺之間移動。為了節(jié)省空間，設(shè)計包括天線下的一個海灣，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.