Dmitry Zelenchuk

Passive Intermodulation in Finite Lengths of Printed Microstrip Lines

This paper addresses the theoretical aspects of passive intermodulation (PIM) generation in printed transmission lines. In order to elucidate the mechanisms of PIM generation, a new model of the transmission line length with distributed nonlinearity is proposed. The developed model has been validated by the near-field measurements of PIM product distributions along the microstrip lines. The contributions of nonlinear mixing, power dissipation, and load matching to PIM products have been analyzed in detail. The obtained results reveal the fundamental properties of PIM generation in finite lengths of printed lines with distributed nonlinearity and identify possible means for PIM mitigation. It was shown for the first time that the reverse PIM products in a matched transmission line with distributed nonlinearity are generated due to nonlinear scattering.

Passive Intermodulation Generation on Printed Lines: Near-Field Probing and Observations

The phenomenological mechanisms of passive intermodulation (PIM) in printed lines have been explored by mapping intermodulation products generated by the two-tone traveling waves in microstrip lines. Near-field probing based upon a commercial PIM analyzer has been employed for identification of the PIM sources in printed lines. The results of extensive near-field probing provide the direct experimental evidences of cumulative growth of the intermodulation products in the matched uniform microstrip lines and reveal the fundamental role of the nonlinear scattering by the lumped nonlinear inclusions in the intermodulation production. The distributed nature of the PIM generation in microstrip lines has been conclusively demonstrated and comprehensively described in terms of the four-wave mixing process that proved to be fully consistent with the results of experimental observations of third-order PIM products on the matched and mismatched microstrip lines.

Millimeter-Wave Printed Circuit Board Characterization Using Substrate Integrated Waveguide Resonators

This paper proposes a substrate integrated waveguide (SIW) cavity-based method that is compliant with ground-signal-ground (GSG) probing technology for dielectric characterization of printed circuit board materials at millimeter wavelengths. This paper presents the theory necessary to retrieve dielectric parameters from the resonant characteristics of SIW cavities with particular attention placed on the coupling scheme and means for obtaining the unloaded resonant frequency. Different sets of samples are designed and measured to address the influence of the manufacturing process on the method. Material parameters are extracted at V - and W -band from measured data with the effect of surface roughness of the circuit metallization taken into account.

Split-Ring FSS Spiral Phase Plate

This letter gives the first report of a planar phase plate structure based on frequency selective surface (FSS) technology for the generation of helical far-field radiation patterns with circular polarization properties. The unit cell of the structure comprises two orthogonal split-ring resonators designed to ensure 180 phase shift between orthogonal transmission coefficients. This property is exploited to obtain progressive rotational phase shift within the structure and thus synthesize 360 spiral phase profile. Measured far-field radiation patterns demonstrate spiral phase front generation for 10-GHz circularly polarized waves transmitted through the structure.

Enhanced transmission in microwave arrays of periodic sub-wavelength apertures

Several configurations of aperture arrays have been investigated using a rigorous numerical–analytical technique. The characteristics of optical transmission through a periodic array of sub-wavelength holes in metal films have been simulated and the mechanisms of the transmittance enhancement ar ed iscussed. The effects of topological factors and array arrangement have been explored from the perspective of enhancing microwave transmission through arrays of sub-wavelength apertures. The features and properties of aperture arrays used in quasi-optical filters and wavelength selective structures are presented.

Carrier-power dependence of passive intermodulation products in printed lines

In this paper, the carrier-power dependence of the PIM products generated in microstrip and coplanar waveguide transmission lines is investigated experimentally. Both simultaneous and independent tuning of the power levels of two fundamental carriers is used. Saturating behaviour of the PIM products at higher carrier power and local minima of PIM products in the two-carrier power domain are observed. The effect of the combined conductor and substrate nonlinearities on the power rates of PIM products is discussed. Application of the PIM power measurements to the characterization of nonlinearity in printed circuits is considered.

Passive intermodulation on microstrip lines

The theory of passive intermodulation generation on printed transmission lines has been proposed. The new model for a terminated section of the transmission line with distributed nonlinear resistance has been developed and verified against the published experimental data. The closed form relation between the macroscopic nonlinear resistance and microscopic nonlinear surface resistivity of strip conductors has been obtained for microstrip lines. Effects of microstrip line width, length and matching on passive intermodulation generation have been studied in detail.

Effect of Laminate Properties on Passive Intermodulation Generation

The results of experimental study of passive intermodulation (PIM) on printed circuit board (PCB) laminates are reported. Comparison of PIM performance of different materials has shown correlation between the PIM level and the laminate physical properties. The effect of the line length on PIM level has been experimentally observed. A simple model has been devised to describe the relation between the line length, attenuation and PIM performance of the lengths of straight microstrip lines.

Circular Polarization Frequency Selective Surface Operating in Ku and Ka Band

A double layer circular polarization (CP) frequency selective surface (FSS) for use as a dual-band quasi-optical diplexer suitable for deployment in reflector antenna systems is described. The FSS was designed to reflect Ku band signals (11.7-12.75 GHz) while transmitting Ka band signals (17.3-20.2 GHz) and conserving CP in each of these bands. The simulated/measured reflection loss over the Ku band was less than 0.05/0.1 dB for both TE and TM polarizations, while the simulated/measured axial ratio was less than 0.2/0.75 dB. Over the Ka band, the simulated/measured transmission loss for both polarizations was below 0.25/0.4 dB and the simulated/measured axial ratio was less than 0.25/0.75 dB. To the best of our knowledge, this is the first report of a metallo-dielectric FSS that simultaneously operates in CP for an oblique angle of incidence in both Ku and Ka bands.

Propagation Characteristics of Groove Gap Waveguide Below and Above Cutoff

Recently, gap waveguides have been shown as a potential alternative to convenational waveguides in the millimeter-wave band. Until now, groove gap waveguide (GGW) has been studied through direct correspondence with rectangular waveguide with the same physical dimensions. However, there have been observed differences in the above cutoff propagation characteristics between these two waveguide types. Furthermore, the behavior of GGW below cutoff remains unknown. This work presents a discussion of both below and above cutoff propagation characteristics of GGW, and introduces a simple model that explains the observed GGW behavior and establishes well its propagation characteristics. Two thru-reflect-line calibration kits have been manufactured, and the measurements have good agreement with the proposed analysis model results.