General Design Technique for High-Gain Traveling-Wave Endfire Antennas Using Periodic Arbitrary-Phase Loading Technique

This article proposes a general design technique for high-gain traveling-wave endfire antennas using a periodic arbitrary-phase loading technique. This work extends the periodic phase-reversal techniques reported in previous work to application scenarios where phase reversals are difficult to realize (e.g., single-layer circuits). It also relaxes the substrate permittivity requirement in phase-reversal techniques. To verify the proposed technique and theory, two design examples using different phases other than
$\pi $
are provided. Double-side parallel stripline and coplanar stripline are employed to provide vertical and horizontal polarizations, respectively. Double-side parallel stripline antenna achieves a maximum endfire gain of 15.6 dBi with vertical polarization. The coplanar-stripline antenna exhibits a maximum endfire gain of 16.6 dBi with horizontal polarization. The experimental results of these two examples validate the proposed technique.