A Fixed-Beam Leaky Wave Antenna With Coupling Elements of Multiresonance

A novel technique is proposed for the fixed-beam design of leaky wave antennas (LWAs) by periodically loading multiresonance elements. The single-resonance elements can generate phase shift with a negative slope in a narrow band for phase compensation, which is used to design an LWA with fixed beam. Furthermore, the fixed-beam bandwidth can be expanded by loading a set of different resonant elements. A design of fixed-beam microstrip LWA using the multiresonance technique is demonstrated and investigated. The antenna consists of a main microstrip line that is periodically loaded with a set of
$L$
-shaped coupling patches of different sizes on both sides. The patches have different resonant frequencies, which act as radiators to generate leaky wave radiation and as resonant elements to compensate for dispersion in a wide operating band. A prototype of the antenna designed for radiating at -14° is fabricated and measured. Measurement results show that the antenna has only a 2.9° beam-squinting in the operating band from 14.2 to 15.7 GHz (with a fractional bandwidth of 10.1%), with a peak gain varying from 11.6 to 14.2 dBi. The bandwidth is almost four times that of the LWA with single-resonance elements loading.