Design of low sidelobe series microstrip array antenna with non‐uniform spacing and excitation amplitude

To reduce the sidelobe level (SLL), a ten‐element non‐uniform microstrip array antenna at 14.25 GHz frequency was designed. This Letter proposes an improved differential evolution algorithm, expanding the optimisation variable from one, the array element spacing, to two, the array element spacing and the excitation amplitude. Then a series linear array antenna with non‐uniform spacing and unequal excitation is constructed, and a uniform spacing Chebyshev array antenna and an equal excitation non‐uniform spacing array antenna are constructed as references. The experimental results show an SLL of −22 dB and a gain of 16.5 dB.