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In this paper, we present the compact bandpass cavity filters for UHF range. We investigate the properties of coaxial resonators with various numbers of tubular posts from one to four. We show that...

Cylindrical waveguiding structures with complex transverse cross sections and application of the structures in modern information and communication systems are reviewed. History of and prospects for development of such microwave elements are considered, and methods for electrodynamic analysis are analyzed. Applications of complex cylindrical waveguide and coaxial structures as basic elements in the systems for generation of signals, radio communications, radars, and sounding are presented.

—The problem of determining the complex dielectric constant of materials in the centimeter and millimeter wavelength ranges is solved using the waveguide method with an double-ridged waveguide. The use of a segment of an double-ridged waveguide as the measuring cell made it possible to expand the operating frequency range and increase the measurement accuracy due to localization of the electromagnetic field energy in the space between metal ridges. The electromagnetic fields of hybrid types of waves in the double-ridged waveguide were calculated by the partial region method taking into account the peculiarities of the electromagnetic field on the metal and dielectric ridges. The results of measuring the complex dielectric constant for samples made of ebonite, Teflon, and fiberglass are presented.

We present a new type of waveguide bandpass quasi-elliptic filter whose resonators are implemented by thin transverse resonant diaphragms with an aperture in the form of a rectangular windo...

We have synthesized elliptic bandpass waveguide filters. The resonators of the filter are thin plane-transverse resonant irises with an aperture in the form of a rectangular window with two metal L-shaped ridges. The electrodynamic problem of calculating the complex conductance of the iris is solved. An equivalent circuit of the resonant iris is proposed, and the correspondence of the geometric size of its aperture to the parameters of the circuit is established. The results of synthesis of an elliptic filter for the WR137 rectangular waveguide with a passband of 6.35–6.83 GHz at a level of −3 dB are presented. The longitudinal size of the filter is 34 mm, which ensures the small size of the developed device.

The paper considers the modeling of the H-waveguide filter. An analysis of its characteristics is carried out. The creation of a computer model for its inclusion in a virtual laboratory is described. In the new lab, the measuring instruments have a completely realistic interface and can be operated by pressing buttons on the front panel.

The problem of electrodynamic analysis of modes structure in a circular waveguide with metal radial T-ridges and layered dielectric filling is solved. The calculation algorithm of cutoff wave numbers, electromagnetic fields components of TE- and TM-waves and propagation constants of hybrid waves taking into account field singularity at metal circular segment of finite thickness have been developed. The dependencies of the normalized cutoff wave numbers and propagation constants on the geometric dimensions of the structure and on dielectric permitivity are investigated. The electromagnetic field's visualization of the main and higher modes for TE- and TM-waves and hybrid waves are shown.

The problem of electrodynamic analysis and synthesis of band-pass waveguide filters on thin resonant metal diaphragms with a complex aperture is solved. A complex aperture is a combination of complementary split ring resonators (CSRRs) and a Koch fractal. The calculation of cutoff wave numbers and the components of electromagnetic fields expressions for have been carried out by the partial regions method, taking into account the features of the electromagnetic field on metal ridges. The results of computer simulation and experimental verification for a three-cavity band pass filter on a rectangular waveguide WR-137 are presented.

The possibility of applying the partial region method to investigate a cylindrical structures with inhomogeneous dielectric filling and a complex cross-sectional shape are presented in this paper. To improve the convergence of the method and to increase the speed of calculating the algorithm at the interface, we used functions that take into account the behavior of the electromagnetic field near metal ridges. The research is carried out to compute the electromagnetic waves propagation constants in a circular waveguide and an analysis is carried out to investigate the dependence of the electrodynamic characteristics on various values of dielectric constant and geometric dimensions.

Computer simulation and synthesis of waveguide selective devices based on circular waveguides with T-shaped metal ridges have been performed. A method for obtaining the initial approximation for further optimization of their characteristics has been described. As basic elements, cavity resonators consisting of sections of circular waveguides with two T-shaped metal ridges are used. The results of simulation of a band-pass filter have been presented.

We solve the problem of electrodynamic analysis of the mode composition of radiation in a circular waveguide with thin radial metal ribs. Algorithms for calculation of cutoff wave numbers and components of the electromagnetic fields of the H and E modes have been developed with allowance for the singularity of the field behavior near a thin metal rib. Spectral characteristics of the waveguide are studied. Structures of the electromagnetic fields of the fundamental mode and the higher modes are determined.

A novel approach to computer simulator development of microwave measurement equipment is presented. The main feature of the software is an interface of the simulator, which is an interactive image of the real equipment allowing to manipulate the keys and other elements of the front panel by the computer mouse. For the measurement procedure, the simulator allows to use analytical formulas or upload the data from the computer models of the microwave devices and from the real measurements in *.s2p format. Implementation of the developed simulator into the educational process provides each student with an unlimited access to the measuring equipment and gives the opportunity not only to study the characteristics of microwave devices but also to gain experience with the real equipment due to interactive computer interface that is completely identical to real front panel.

We consider an algorithm of calculating the characteristics of the fields of hybrid modes in waveguides with complicated cross sections. The presented algorithm makes it possible to allow for the specific features of the behavior of the electromagnetic-field components near the dielectric and metal ribs of the waveguide. The results of calculating the electrodynamic characteristics of the hybrid HE and EH modes in a Π-shaped waveguide with layered and piecewise-layered dielectric filling are reported. The tables of cutoff wave numbers are presented, and the structures of electromagnetic fields of hybrid modes are shown. The results obtained by using the method proposed and the numerical methods are compared.

The article considers the algorithm for calculating characteristics of fields of hybrid types of waves in waveguides with complex cross sections. The presented algorithm takes into account the sing...

The novel configuration of pass-band filter on rectangular H-plane cavities are presented in the paper. In usual cascade pass band filter cavities are located in series. However, in investigated structure cavities are located in one cross section of waveguide. The proposed filter configuration can be presented as separate filters of the first kind. Every so elementary filter can be computed independently from other filters, which is provided by single possible location of cavity in filter’s cross section. It greatly simplifies the production of band pass filters, especially filters with multiple transmission zeros. A computer model of the transverse filters is simulated to test the method, and the corresponding measurements are made.

This paper provides information about the results of investigation of circular dielectric filled waveguide with metal ridges. One of the most important characteristics of waveguide structures are cutoff wave numbers. In our research we focus on cutoff wave numbers of the dominant mode and higher order modes. So, the method which is applied is the partial regions method. The researched structure has metal ridges and corners so a singularity of electromagnetic fields is considered by adding special functions in equations. Equations for electromagnetic field components are presented. Besides cutoff wave numbers the pictures of isoline of electromagnetic field are obtained. These results can be useful to create filters, diplexers and others devices based on circular dielectric filled waveguide with metal ridges. The computed results are found for different number of series terms in expansion and different numbers of approximating functions, so it allows to estimate the accuracy of the algorithm.

The novel type of coaxial resonator for the cavity filter is presented. The proposed resonator consists of series overlapping each other coaxial tubular metal posts. It was shown that such multi-cylinder coaxial resonator has significantly lower resonant frequency than resonator with one metal post. The corresponding bandpass filter for the 690–806MHz frequency band was developed and manufactured. For the 5-th order filter the achieved volume is 110 cm3. The measured return loss in the passband is −20 dB and the insertion loss is less than −0.25 dB.

The synthesis of waveguide band-pass elliptic filters is realized. The thin transverse resonance diaphragms with an aperture in the form of a rectangular window with two metal L-shaped metal ridges are used as resonators of the filter. An equivalent circuit of a resonant diaphragm is proposed. The synthesis results of an elliptic filter for a rectangular waveguide WR137 with a bandwidth of 9,2% and length of 64 mm are presented.

The problem of the electrodynamic analysis of electromagnetic fields of circular metal waveguide with thin metal ridges and unhomogeneous dielectric filling is solved. The calculation algorithm of cutoff wave numbers and components of electromagnetic fields of quasi-TE-waves taking into account field singularity at thin metal ridges is developed. The visualization of electromagnetic fields is presented

Results of the electromagnetic analysis of single pin resonant elements in ridge rectangular waveguides are presented. The equivalence of scattering characteristics of pin elements and thin flat transverse diaphragms is shown. Electromagnetic fields and cutoff wave numbers of ridge waveguides are determined by the partial domain method taking into account the field singularity at the edge. Results of the synthesis of a three-resonator band-stop filter with a stopband of 7.5% and a passband reflection level of no more than–20 dB in the entire waveguide operation band are presented.

The solution of the problem of spectral electrodynamic analysis of a circular waveguide with radial metal ridges and with thin flanges is presented. The calculation algorithms of cutoff wave numbers and components of electromagnetic fields of TE- and TM -waves are developed on the basis of the partial regions method taking into account field singularity at metal ridges. The spectral characteristics of the waveguide are investigated. The visualization of electromagnetic fields patterns of the dominant and higher order modes is realized.

In this paper a method of computer modeling of measurement devices and instruments is described. A software package for virtual laboratory creation is developed. Models of measurement devices have user interface identical to real devices and can simulate the behavior of various devices. The created models of virtual measurement devices can be implemented for experimental data analysis provided in common used format *.s2p.

The general case of diffraction of nonsymmetrical TM vp and TEvp modes on irregularity in circular waveguide is discussed. The calculation is performed on the basis of the method of partial areas taking into account the features of the electromagnetic field at the metal edge. The high accuracy of the method is demonstrated.

A broadband method for measuring the complex permittivity of materials for the microwave range is proposed. The double-ridged waveguide is offered to use as a measuring cell. The developed method makes it possible to increase the accuracy of determining the complex permittivity of materials by placing the sample between the waveguide ridges at the maximum of the electric field intensity of the fundamental wave. Electrodynamic characteristics of the double-ridged waveguide with a dielectric sample are presented: cutoff frequencies, propagation constants, and the structure of the fundamental hybrid wave at the operating frequency. The measurement results of the complex permittivity of a Teflon sample are shown.

The original approach to the computer modelling of the modern measuring equipment is presented. The interface of the computer model is an interactive photo of the real device with all buttons operation available by the PC mouse. The models of the devices can be combined in the measuring stands in arbitrary order and provide a variety of virtual laboratory works. As an example, the computer models of the Vector Network Analyzers Rohde&Schwarz ZVA40 and Keysight Technologies E8363B PNA are presented. The measuring data of the investigated microwave devices can be provided by the analytical formulas, by the computer simulation, and by the measured resultes of the real devices stored in *.s2p files.

The solution of the problem of spectral electrodynamic analysis of a circular waveguide with radial metal ridges is presented. The calculation algorithms of cutoff wave numbers and components of electromagnetic fields of TE- and TM-waves are developed on the basis of the partial regions method taking into account field singularity at metal ridges. The spectral characteristics of the waveguide are investigated. The visualization of electromagnetic fields patterns of the dominant and higher order modes is realized.

The new technique for measuring the complex permittivity of materials in a wide microwave frequency range has been developed. The double ridged waveguide has been used as a measuring cell. The proposed technique allows to increase the accuracy of measurements by placing the dielectric sample between the ridges of the waveguide, in the place of maximum concentration of electromagnetic energy of the fundamental wave. For the double ridged waveguide with dielectric filling, electrodynamic characteristics have been calculated, such as propagation constants and cutoff frequencies. The structure of the fundamental HE-wave at the operating frequency has been determined and visualized. The measurement results of the complex permittivity of the ebonite sample have been presented.

The synthesis of waveguide band-pass elliptical filters is realized. The thin transverse resonance diaphragms with an aperture in the form of a rectangular window with two metal L-shaped ridges are used as resonators of the filter. The electrodynamic problem of calculating the complex conductivity of the diaphragm is solved. An equivalent circuit of the resonant diaphragm is proposed and the correspondence between the geometric dimensions of its aperture and the parameters of the circuit is determined. The synthesis results of an elliptic filter for a rectangular waveguide WR137 with passband of 7,5% and length of 34 mm are presented.

We solve the problem of electrodynamic analysis of a complex waveguide resonance diaphragm with an aperture in the form of a rectangular window with two centrally symmetric L-shaped ridges. The properties of the diaphragm are studied on the basis of the analysis of the imaginary part of its normalized conductivity. Critical wave numbers and electromagnetic fields are calculated by the partial region technique allowing for the singularity of the electromagnetic field on metal ribs. It is shown that the imaginary part of the normalized conductivity of the diaphragm as a function of the frequency not only turns to zero, but also contains a discontinuity of the second kind, which corresponds to the parallel and series resonance.

The problem of electrodynamic analysis and synthesis of band-pass microwave filter based on L-ridged rectangular waveguide is solved. The possibilities of multilevel substrate integrated waveguide (SIW) filter structure implementation for ridged rectangular waveguides are discussed. The compact SIW filter with 4% pass-band and a stop-band attenuation level −60 dB is described.

The problem of electrodynamic analysis and synthesis of compact microwave filter based on complex resonant transverse diaphragms in rectangular waveguide is solved. The proposed aperture of thin metal diaphragms is the rectangular window with two metal L-shaped ridges. In attempt to reduce the filter dimensions, the capacitive metal diaphragms are added instead of the quarter-wave invertors. The received band-pass filter has the solid multilayered metal-dielectric structure and possesses 10% pass-band and the 8 mm length.

The article describes the algorithm of calculating the electromagnetic fields of hybrid modes in the ridged waveguide with piecewise-layered dielectric filling. Electrodynamic calculations performed by the method of partial regions including the electromagnetic field singularities at the dielectric and the metal edges of the waveguide. The structures of the hybrid HE- and EH-waves in the ridged waveguide comprising two dielectric plates are visualized.

The electrodynamic analysis of new types of metal resonant diaphragms with complex aperture on the surfaces of dielectric layers is derived and the synthesis of compact waveguide band-pass filter on WR-90 is provided. In attempt to reduce the filter dimensions, the capacitive metal diaphragms are added instead of the quarter-wave invertors. The three-resonator band-pass filter was synthesized on the basis of metal diaphragms with the aperture in a form of rectangular window with two L-shaped metal ridges and capacitive diaphragms. The band-pass filter possesses 10% and the length is only 8 mm.

We solve the problem of electrodynamic analysis and synthesis of bandpass filters based on rectangular waveguides with complex L-shaped ridges. Cutoff wave numbers and components of the electromagnetic field were calculated by the partial region method with allowance for the singularity of the electromagnetic field on metal ribs. As a prototype, the model of a cutoff filter and an approximation of its amplitude-frequency characteristic by the Chebyshev polynomials were used. Examples of synthesis of narrow-band filters with inputs based on a rectangular waveguide and an H-waveguide are presented. Advantages of using a novel waveguide with a complex cross section in the filter are considered, including the appearance of a total reflection frequency (antiresonance) in the filter rejection band, which allows one to significantly extend this band and increase the attenuation level in it.

New design approach and software package for computer modeling of virtual education laboratory works is proposed. Measurement equipment in virtual laboratory has interface and behaviors which are identical to real devices and allow studying characteristics of UHF devices and elements.

The problem of the electrodynamic analysis and synthesis of the waveguide band-pass filters on complex resonant diaphragms is solved. The diaphragms with an aperture in the form of a rectangular window with two metal L-shaped ridges are used. The possibility of creation by means of these diaphragms of compact and high Q-factor waveguide filters is shown. The approach allowing reducing significantly the longitudinal size of filters by use as impedance inverters of capacitive diaphragms instead of quarter-wave sections is offered. The practical realization of filters is enabled by drawing metallization on thin dielectric substrates. A good theoretical and experimental result matching is shown. The possibility of reduction of the longitudinal size of filters to three times in comparison with a classical quarter-wave design is confirmed.

The method of computer simulation of microwave devices and special laboratory workshops is described. Simulated laboratory has a module structure. The basis for constructing a model of the specific workshop is a concept of the abstract “device” with layout is identical to the installation of a real one. The software interface allows changing the configuration and frequency tags to carry out all necessary measuring characteristics.

The problem of electrodynamic analysis and synthesis of band-pass microwave filter based on complex resonant transverse diaphragms in rectangular waveguide is solved. The aperture of thin metal diaphragms is the rectangular window with two metal L-shaped ridges. The compact waveguide filter with 6% pass-band and a high stop-band attenuation level is developed and measured.

A technique of electrodynamic analysis and synthesis of directional couplers based on Π-shaaped waveguides with a system of small coupling apertures is reported. Parameters of coupling between two waveguides through a small aperture are calculated within quasi-static Bethe’s theory. Critical wavenumbers and components of the electromagnetic fields of ridged waveguides are calculated with allowance for the features of the electromagnetic field on the edge. The characteristics of synthesized directional couplers based on Π-shaped waveguides with coupling along the wide wall of 20 and 10 dB are reported.

A technique of electrodynamic calculation and computer-aided simulation of the structure of the electromagnetic fields of TE and TM waves in a rectangular waveguide with two L-shaped ridges and a lossless air filling is presented. The problem is solved by means of the partial domain method with allowance for the edge singularity of the electromagnetic field. Cutoff wave numbers, the structure of the electromagnetic fields of various TE — and TM-wave modes in the cutoff regime, the characteristic impedance, and the breakdown power for the fundamental waveguide mode are calculated.