Universal and Non-Iterative Design Method for In-Phase Radiation of Microstrip Traveling-Wave Series-Fed Antenna Arrays

Synthesis and Realizability in Design of Minimum-Simulation Inline Antenna Arrays

“…For in-phase recombination in a direction different from broadside or if a non-uniform-phase illumination is used (such as side-lobe suppression methods like [16] or using [9] to compensate for mutual coupling by altering phase and amplitude tapering), the adjustment phase delay determined via (18) must be altered according to the desired tilt angle from broadside and physical spacing between the elements.…”

“…Conversely, an additional phase delay ϕ 1 on port 1 of the core element (S 11 ← S 11 e −2jϕ1 , S 21 ← S 21 e −jϕ1 , S R1 ← S R1 e −jϕ1 ) does alter the operating power gain surface and hence the available z I , ϕ I contour pairs and the corresponding mapping phase shifter. This countermeasure, however, can only help limitedly, since just the B quantities in (9) are affected in the gain surface, and the gain bounds of (21) still remain. An additional delay ϕ 1 is not thus sufficient to address the third failure possibility: in these cases, a different core element must be chosen, although possibly only in the unrealizable sections of the array.…”

“…Relevant to the array synthesis, instead, are the scattering parameters at 21 GHz and the polarized field component in the observation point when fed alternatively with 1 W from port 1 (giving 26.1 mV/ m with phase 174 • while port 2 is closed onto a 50 Ω load) and from port 2 (26.1 mV/ m with phase 354 • while port is 1 closed onto a 50 Ω load), normalized to 2) Considerations: The considered core element creates the G P surface of fig. 4, evaluated via (9). The operating gain for z I = 1 is G IC C = 0.8147, from (10).…”

“…Non-uniform illumination is often used for sidelobe reduction, null placement, beam shaping but also when mutualcoupling compensation techniques are used, such as [9].…”

“…• requires in principle only one electromagnetic simulation of a core 2-port antenna without additional assumptions; • allows to design with closed formulas an inline array of core elements connected by transmission lines; • neglects mutual coupling between the radiators; crosscoupling compensation can be however applied [9]; • does not require equivalent models of the core element;…”