A Slow-Wave Rat-Race Coupler Using Substrate Integrated Suspended Line Technology

Compact cell topology selection for size-reduction-oriented design of microstrip rat-race couplers

“…Table shows a comparison of the proof‐of‐concept prototype devices presented in this work with recent state‐of‐the‐art compact RRCs from the literature . The assessment of these structures, based primarily on circuit miniaturization ratio, but also fractional bandwidth, reveals that the obtained design solutions belong to the smallest in the literature (92% as in).…”

“…Table 3 shows a comparison of the proof-of-concept prototype devices presented in this work with recent stateof-the-art compact RRCs from the literature. 10,14,[23][24][25][26][27][28][29][30][31] The assessment of these structures, based primarily on circuit miniaturization ratio, but also fractional bandwidth, reveals that the obtained design solutions belong to the smallest in the literature (92% as in 14,27 ). At the same time, the proposed designs feature wider bandwidths when compared with the smallest reported couplers, which showcases the reliability of the demonstrated methodology.…”

“…The initial class of methods developed to address this stipulation involved decreasing the guided wavelength by utilizing high‐permittivity substrates such as ceramics or artificially engineered materials with periodic discontinuities (inclusions, cavities, etchings) inserted in the dielectric or the ground plane metallization . The increased cost and complexity of circuit fabrication introduced by the above‐referred methods led to the formulation of an alternative approach to size reduction of microwave devices, based on rerouting of ordinary transmission lines using line meandering or fractal curves . Although this concept may provide outstanding miniaturization ratios (eg,), its effective application is restricted to narrow metal traces.…”

Rapid design closure of microwave components by means of feature-based optimization and adjoint sensitivities

“…Design closure using full‐wave electromagnetic (EM) simulations is nowadays a commonplace and often a necessity in microwave engineering . In many cases, simpler models, such as equivalent circuit ones, provide insufficient accuracy, e.g., due to considerable EM cross‐couplings in densely arranged layouts of miniaturized structures .…”

“…Design closure using full-wave electromagnetic (EM) simulations is nowadays a commonplace and often a necessity in microwave engineering. 1,2 In many cases, simpler models, such as equivalent circuit ones, provide insufficient accuracy, e.g., due to considerable EM cross-couplings in densely arranged layouts of miniaturized structures. 3 Furthermore, various parasitic phenomena (e.g., skin or proximity effects in case of integrated inductors 4 ) or environmental components (connectors, 5 or radomes in case of antenna structures 6 ) have to be accounted for, which can only be done by means of EM analysis.…”