S.V. Melnikov 1, S.A. Pschenichnyi 2

1,2 JSC «All-Russian Scientific Research Institute «Gradient» (Rostov-on-Don, Russian)

1 2130@gradient-rnd.ru, 2 pshenichny@gradient-rnd.ru

At the present time the main trends in design engineering of multifunction microwave range devices are following: complexity factor increase of microwave modules, decrease of equipment mass and dimensions parameters and wide use of assembly planar technology. Necessity for functional saturation increasing of devices on retention of the tendency for further miniaturization gives rise to conception of more effective use of multilayer printed circuit board volume. Elements on integrated in base plate transmission line links are used for this purpose, microwave chips are installed in cages shaped in printed-circuit board, strip-line filters are installed at printed-circuit board buried-layer planes but control and commutation elements are remained behind outside layer.

At the present time low temperature cofired ceramic (LTCC) technology is known, being used for manufacturing of multilayer boards on ceramic bottom, that makes it possible to use metals with low resisitivity such as argentum, aurum or mixtures of argentum with palladium and platinum as conductors due to relatively low burning temperature (850−875°С). LTCC technology keeps a variety of unquestionable advantages for mass production though it keeps disadvantages in conditions of one-off and small-batch production which includes: necessity for availability of own large-scale production-technological base, for device interface engineering, development and manufacturing implementation, including more than ten of expensive foreign-made and home-made machines and units; used equipment appreciation high cost; production load support problem for economic viability providing.

Ascending requirements to equipment mass and dimensions parameters as well as demand for design simplification and maintainability increasing require from designers of microwave range hybrid units solving significant quantity of technical problems such as: mutual coupling exclusion of jointly located functional assemblies; providing of required internal wirings of assemblies without failure of wave resistance similarity; collocation of planar elements and elements realized on the basis of bulk structures; providing of reliability, temperature stability of parameters; ease providing of control and adjusting if it is necessary; providing of high screening degree of supply and control circuits, and others. Embedded structure technology asserts arranging of topologic filters on multilayer printed circuit board buried-layer planes. Multilayer printed circuit board outside layers are used for arrangement of commutation and stepping up elements, post filtration of parasite band-pass ranges of distributed filters and low-frequency lumped component filters. The nearest creation method device and approaches of realizing of similar devices are described in [2]. Embedded structure technology has no LTCC technology disadvantages and at the same time has advantages: relative cheapness; technology maturity; availability of high-quality relatively cheap MWF materials (RO4003 and others); personnel experience effective use without retraining necessity; high technologic ease of assembly of ready-made devices, use of high-efficiency processes of component automated placement and group soldering; high screening degree of embedded structures; no less than twofold ready-made device downsizing. The example of device developed and manufactured by embedded structure technology is given – preselector on gated filters carrying thirteen channel filters, nine of which are strip-line filters with band – 100…3200 MHz. Preselector includes preliminary low noise amplifier (LNA) and operated attenuator. Strip-line filters are rested on printed circuit board buried-layer planes, screening coefficient exceeds 65 dB. Defined requirements to preselector were implemented without iterates. Embedded structure technology utilization makes it possible to get high technical characteristics at MWF module substantial size reduction and depletion.

Melnikov S.V., Pschenichnyi S.A. Embedded microwave frequency structures, use in practice and implementation specialties. Radioengineering. 2020. V. 84. № 11(22). P. 70−74. DOI: 10.18127/j00338486-202011(22)-13. (in Russian)

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