Optimised Meandered Microstrip Feeds for Planar Antenna Arrays

This paper considers utilization of meandered (serpentine) microstrip lines as feeds in planar multylayer phased array antennas. Nevertheless, that these structures have radiating properties itself and they are used as travelling-wave antennas [1], however, they can be optimized to have predictable performances as antenna feeds in respect of transmitted phase and magnitude. Substantial problems of these lines, the resonance attenuation and phase delay can be avoided with properly chosen resonance ¿-junction length of the serpentines. The paper contains results from numerical optimization of regular and non-regular meandered feeds obtained by MoM-based simulator and compared with measurements in Ku-band. Finally, design rules are formulated for meander parameters that allows of avoiding resonance losses and unpredictable phase delay of antenna feeds in desired frequency range.