A narrow via-free composite right/left-handed leaky wave antenna with low cross-polarization

A frequency scanned leaky wave antenna is proposed and designed for operation in X-band. The guiding structure is realized as a composite right/left-handed transmission line composed of planar, periodically arranged via-free unit cells, implemented in microstrip technology. The main focus of the work was on the optimization of the electric field polarization characteristics. Hence, a cross-polarization level is achieved which is at least 20 dB below the co-polarization. The resulting maximum gain of the antenna is 13.7 dBi with a beamwidth of 9.5°. Furthermore, several of these narrow leaky wave antennas could be arranged in parallel resulting in an array with a clearance of less than half of a free space wavelength and allowing grating lobe free operation.