Series-fed microstrip patch arrays are light weight, low profile antennas typically used for communication and in microwave sensor applications. The traveling-wave series-fed patch array is related to the resonant series-fed patch array (already included in the Antenna Magus database), but has a different design approach and operation mechanism, providing different performance characteristics and options. Where the resonant series-fed patch array provides in-phase excitation for efficient broadside radiation, the patches of the traveling wave array are spaced to produce a progressive phase shift between patches. This results in a fan beam which squints off broadside and scans with frequency.
The traveling-wave design can achieve high gain (up to 20 dBi) at a specified squint angle. As with most traveling-wave array structures (like slotted guide arrays), the operating bandwidth is narrow (typically 2%), and some energy is absorbed in a termination load resulting in a reduced radiation efficiency (typically in the order of 75%). The Antenna Magus design provides 0.5% to 5% bandwidth design options and attempts to optimize the radiation efficiency according to the designed objectives....Typical fan beam pattern of a 12 element array. Gain patterns vs frequency of a traveling wave series-fed array designed for 18 dBi gain and a 10 degree squint at 10 GHz. [Note how the main beam scans with frequency].