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Dual‐band filtering power divider with unequal power division ratio and low‐loss characteristic
Author(s) -
Shao Chuan,
Xu Kai,
Zhu XiaoHua,
Shi Jin,
Chu Hui
Publication year - 2020
Publication title -
international journal of rf and microwave computer‐aided engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.335
H-Index - 39
eISSN - 1099-047X
pISSN - 1096-4290
DOI - 10.1002/mmce.22149
Subject(s) - power dividers and directional couplers , wilkinson power divider , resonator , multi band device , resistor , current divider , electrical impedance , division (mathematics) , transmission line , electrical engineering , electric power transmission , frequency divider , transformer , power (physics) , electronic engineering , engineering , topology (electrical circuits) , mathematics , physics , voltage , arithmetic , quantum mechanics , antenna (radio)
In this article, a dual‐band filtering power divider with unequal power‐division ability is proposed. Different from conventional equal power dividers constructed by filters or coupled resonators, noncoupled structures are employed in this design. As a result, low‐loss characteristic is realized for the proposed power divider. In this proposed structure, the dual‐band unequal power allocation is realized by replacing conventional single‐band λ/4 transformers with dual‐band ones (T‐junction structures). Three identical λ/4 stepped impedance resonators are properly attached to all the three ports of the proposed power divider to generate an extra transmission zero between two operational bands. Therefore, a filter‐like shaping in its S‐parameter results is obtained. A resistor is located between two outputs for output isolation. Mathematical derivations of the overall design procedure are also provided based on the circuit models and transmission line theory. Meanwhile, a resistor for output isolation is also included between two outputs, whose value can be calculated using given equations. For validation, a prototype operating at 0.9 and 2.1 GHz are designed, fabricated, and measured. The isolations between two outputs are 30 and 26 dB while the phase differences are only 2.5°and 4.9° at 0.9 and 2.1 GHz in the measurement, indicating good consistence of outputs. Measured |S21| and |S31| are −(1.76 + 0.3) dB, −(4.77 + 0.2) dB at 0.9 GHz and −(1.76 + 0.6) dB, −(4.77 + 0.5) dB at 2.1 GHz.