Design of tri-band microstrip antenna with shared aperture on flexible single-layer

To get multi-band antenna with reduced system load, we propose tri-band antennas utilizing shared aperture array which works in S-band, X-band and Ku-band, where three kinds of series-corporate microstrip antennas are interlaced on the flexible substrate. With the orthogonal polarization, layout of antenna arrays is optimized to ensure high channel isolation of antenna arrays’ different ports. The simulated results show the designed antennas having gain of 10.8 dBi, 11.8 dBi and 17.6 dBi respectively for S-band, X-band and Ku-band incidence. The side-lobe level (SLL) for S-band is -23.5 dB with return loss bandwidth of 50 MHz, while Ku-band antenna is -18 dB with bandwidth of 600 MHz respectively. And the bandwidth of circular polarization axial ratio (AR) less than 3 dB is around 1.1% for X-band. The isolation is better than - 40 dB among different ports of all arrays. Furthermore, the designed antennas can be flexibly covered on curved cylinder surface, maximum radiation gain is 2.4dBi, which is better than that of flat when the bending radius is 600mm for S-band. The proposed flexible microstrip antenna can be applied for conformal antennas, which shows great potential for flexible electronic device.