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Author: search.filters.author.Pakasiri, ChatrpolSubject: search.filters.subject.UHF

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    A UHF compact complex impedance-transforming balun with high isolation
    (2020-01-01)
    Nithiporndecha, Kittipong
    ;
    Pakasiri, Chatrpol
    Background: A compact complex impedance-transforming balun for UHF frequencies, which is based on a coupled-line structure that matched all ports and provided high output port iso-lation, was designed in this paper. Methods: A lumped component transformation was used to minimize circuit size. The implemented circuit operated at 433 MHz with the reflection coefficients less than-16 dB at all ports, 0.22 dB amplitude balance and 180° phase balance at the output ports. The signal coupling between the output ports was-16.8 dB. The circuit size is small at 0.032λ. Results: Complex impedance-transforming baluns were designed to operate at 433 MHz. The source impedance at port 1 was set at Z<inf>s</inf> = 12-j12Ω and the load impedances at port 2 and 3 were set at Z<inf>L</inf> = 80 + j30Ω. Conclusion: A compact complex impedance-transforming balun at UHF frequency, with all ports matched and high isolations, was designed and illustrated in this paper.
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    A compact UHF dual-band rat-race coupler with complex impedance load
    (2018-10-01)
    Pakasiri, Chatrpol
    ;
    Wang, Sen
    A compact UHF dual-band rat-race coupler with complex terminated loads is proposed. The design procedure starts with design circuit with transmission line (TL) components, and design equations are also detailed in this letter for dual-band operation. Moreover, the circuit size is further reduced by replacing the TLs with lumped components. An example circuit operating at 450/900 MHz is given. The measurement shows that the circuit has the reflection coefficient at the input port less than −13 dB, the transmission coefficient greater than −5.6 dB and phase difference less than ±10° at the output ports.