Design of an X/Ka dual-band co-aperture broadband microstrip antenna array

This paper presents a novel design of X/Ka dual-band co-aperture microstrip antenna array. Compared with other types of co-aperture antennas, its significant advantage is the slight interference between the two bands´ antennas. In addition, it also has some other good features, such as broadband, low side-lobe. The antenna is designed and simulated, and a test antenna is fabricated and measured. The simulated results match well with the measured ones. The measured impedance bandwidth (VSWR≤2) of the test antenna reaches 18% for X-band and 9.4% for Ka-band. In the working bands, the measured gain is higher than 22dBi and 20.5dBi, the measured side-lobe level is lower than -18dB and -15dB for X- and Ka-bands, respectively. The slight interference between the two bands causes only 1 dB enhancement of the side-lobe level and has nearly no impact of the gain.