Title :
A Balanced-to-Unbalanced Microstrip Power Divider With Filtering Function
Author :
Kai Xu ; Jin Shi ; Longlong Lin ; Jian-Xin Chen
Author_Institution :
Electron. & Inf., Nantong Univ., Nantong, China
Abstract :
In this paper, a balanced-to-unbalanced microstrip power divider based on branch lines with several stubs and one resistor is proposed. The functions of power dividing, frequency selectivity, isolation between output ports, and common-mode suppression can be realized at the same time. The even-odd-mode equivalent circuits combining with the standard S-parameters and the mixed-mode S-parameters are adopted to derive the analytical equations at the center frequency. One or two transmission zeros can be achieved to enhance the out-of-band suppression. The center frequency, bandwidth, isolation, common-mode suppression, and the frequencies of transmission zeros can be controlled by the design procedure. To verify the theoretical prediction, two fabricated prototypes are designed and compared. One gets 7.7% 1-dB bandwidth with 0.6-dB insertion loss and one transmission zero. The other gets 1-dB bandwidth of 5% with 0.7-dB insertion loss and two transmission zeros. The isolation and common-mode suppression for both prototypes are better than 15 and 20 dB within the whole passband, respectively.
Keywords :
S-parameters; equivalent circuits; microstrip filters; power dividers; balanced-to-unbalanced microstrip power divider; branch lines; common-mode suppression; even-odd-mode equivalent circuits; filtering function; frequency selectivity; insertion loss; loss 0.6 dB; loss 0.7 dB; mixed-mode S-parameters; out-of-band suppression; power dividing; transmission zeros; Bandwidth; Filtering theory; Integrated circuit modeling; Microstrip filters; Passband; Ports (Computers); Power dividers; Balanced-to-unbalanced; common-mode suppression; even–odd mode; filtering; power divider;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2015.2445051