Design of Traveling-wave Series-fed Microstrip Array with a Low-side Lobe Level

A design procedure for traveling-wave series-fed microstrip array with a low sidelobe level (SLL) was proposed. To control the radiated power while suppressing the reflection for each antenna element, three types of microstrip antenna elements were introduced, and design parameters were studied. To validate the design procedure, a traveling-wave series-fed array was designed to operate at 76.5 GHz. The performance of the array was measured at an anechoic chamber. The results show stable gain and half-power beamwidth (HPBW) over the frequency range of 75 and 78 GHz, where the SLL was consistently lower than −17 dB.