M.S. Samsonov – Head of PCB Laboratory,

JSC «SPE «Radiosvyaz» (Krasnoyarsk)

E-mail: tybamaks90@mail.ru

Ya.F. Bal’va – Ph.D. (Phys.-Math.), Research Scientist,

Institute of Physics L.V. Kirensky SB RAS (Krasnoyarsk, Akademgorodok)

E-mail: ya.f.balva@iph.krasn.ru

M.O. Savishnikov – Post-graduate Student,

Siberian Federal University (Krasnoyarsk)

E-mail: savishnikov2012@yandex.ru

V.S. Denisenko – Post-graduate Student,

Siberian Federal University (Krasnoyarsk)

E-mail: blovef1@gmail.com

K.V. Lemberg – Ph.D. (Phys.-Math.), Research Scientist,

Institute of Physics L.V. Kirensky SB RAS (Krasnoyarsk, Akademgorodok) E-mail: klemberg@kirensky.ru

Microwave frequency selective devices and bandpass filters, in particular, are among the most important elements of communication systems, radar, radio navigation, various measuring and special radio equipment. In recent years, developers of radio electronic equipment have been paid a great attention to filters with ultra-wide passbands. The usage of broadband signals is dictated by a requirement to increase the speed of data transfer, which is known to be directly related to the operating frequency bandwidth. One of the well-known approaches to the design of ultra-wideband filters is a cascade connection of upper and lower frequency filters. With this approach a selectivity of a wideband filter is determined primarily by the frequency-selective properties of their low-pass filters (LPF). Thus, it is important and actual to study both known LPF designs with the purpose of improving their limiting characteristics and search for new technical solutions to create devices with better selectivity in comparison with known analogues.

A new design of a miniature LPF, made on a suspended dielectric substrate with a double-sided pattern of strip conductors, is studied in this paper. Systematic studies of an influence of design parameters of the studied LPF on its frequency-selective properties are carried out. On the basis of the proposed design, the 5-order LPF was synthesized and fabricated on the alumina substrate with relative dielectric constant 9,8 and thickness 0,5 mm. The filter cut-off frequency is 1,75 GHz, VSWR is 1,2 and a 100 dB-stopband extends to the frequency of 8 GHz. The minimum in-band loss of the fabricated filter was only 0,15 dB. It should be noted that the size of the filter can be significantly reduced by using thinner substrates or substrates with higher relative dielectric constant.

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