V.P. Smirnov, L.D. Starik, D.Yu. Dikarov

The technique of direct synthesis and parameterization of elements in band-passed filter-transformers (BPFT) of even order N ≥ 4 (4-6-8-10-12 ...), based on LC and CL non-resonant sections (NRS), is presented in the article for a first time. Such BPFT, synthesis of which starts from a choice of LPF prototype, acquires ability to a matching unequal loads at the input and output of the filter. Usually, the BPFT consists of two parts. One of them includes cascade-connected base blocks (BB), formed from pairs of LPF and HPF non-resonant sections (LC and CL), which realize the matching of loads by transforming their resistances. The second part of BPFT scheme, which is of the order Nrs = N–4k (k is the number of BB with NRS), contains oscillatory circuits, i.e. resonant sections (RS) with parameters, that are renormalized for a bandwidth that is formed in the BB with NRS and must be the same in all RS. Expressions for calculations by direct synthesis of the NRS parameters or the BPFT with orders N = 4k = 4, 8, 12 are developed and generalized to the case k > 3. It is shown that a band-pass at the loads matching depends on the number of NRS-based BB in the BPFT. The verification of the direct synthesis method was carried out using on the simulations of three BPFT with N = 12, k = 1, 2, 3, based on the LPF prototype Chebyshev 0.5 dB, No = 6, in the AWR Design Environment v. 9.0. The same method of synthesizing parameters the elements of BPFT with an NRS of order N > 4 is implemented using LPF prototypes with a non-traditional, modified Chebyshev approximation, which improves the quality of matching loads.

Smirnov V.P., Starik L.D., Dikarov D.Yu. Synthesis of elements parameters of band-pass filter-transformers, using LC- and CL-non-resonant sections, for the orders N ≥ 4. Radiotekhnika. 2023. V. 87. № 3. P. 132−147. DOI: https://doi.org/10.18127/j00338486-202303-13

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