A hybrid-cascade (HC) coupled-line phaser configuration is presented to synthesize enhanced group delay responses for high-resolution RadioAnalog Signal Processing (R-ASP). Using exact analytical transfer functions, the superiority of HC coupled-line phasers over conventional transversally cascaded C-section phasers is demonstrated and verified using full-wave simulations.Introduction: Radio-Analog Signal Processing (R-ASP) is defined as the real-time manipulation of signals in their analog form to realize specific operations enabling microwave or millimeter-wave and terahertz applications ASP. The heart of an R-ASP system is a phaser, which is a component exhibiting a specified frequency-dependent group-delay response within a given frequency range. Such phasers have found useful applications in the domain of instrumentation, security, short-range communication and RADAR systems, to name a few [1].A common requirement in high-resolution R-ASP is to achieve high dispersion in phasers, in order to provide large frequency discrimination in the time-domain [2]. This translates into the requirement to achieve a large group delay swing in the phaser within the desired bandwidth. Recently, a coupled-line phaser based on composite right/left-handed (CRLH) transmission lines was proposed utilizing its tight coupling property to achieve this goal [2]. However, considering its design complexity, multilayer configuration and fabrication sensitivity, a new configuration based on hybrid-cascaded (HC) coupled-lines was proposed in [3]. This configuration exploits the fact that the required coupling level can be relaxed by folding the conventional C-section into a cross-shaped structure, where superior effective backward coupling results from the discontinuities introduced by the arms of the cross. Consequently, tight coupling coefficients are achieved using different coupled-line sections of relatively small coupling values [4]. This paper demonstrates the advantage of using HC coupled-line phasers over regular cascaded C-section phasers in group delay engineering via both analytical and full-wave simulation results.

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