A Novel Substrate-Integrated Suspended Line Stacked-Patch Antenna Array for WLAN

A novel stacked-patch antenna based on substrate-integrated suspended line technology is proposed. The antenna is designed to be self-packaged using five substrate layers with embedded air cavities. Via is utilized to connect the antenna driven patch with the feed line, and then resonant frequency at 5.2 GHz is generated. U-shaped slot is etched on the antenna driven patch for impedance matching. In order to further extend the impedance bandwidth, a stacked patch with slant slot is introduced and then another resonant frequency at 6.2 GHz is produced. According to the measured results, the antenna element achieves a fractional bandwidth of 17.5% from 5.2 to 6.2 GHz and gain of 9.7 dBi. Based on the antenna element, the eight-element antenna array with feeding network is presented. The microstrip-slotline balun is introduced in the feeding network to achieve 180° phase difference with equal amplitude so that symmetrical radiation patterns are achieved. Simulation and measurement results for the proposed antenna array are in good agreement. In the frequency band from 5.28 to 6.05 GHz, antenna gain of 16.24 dBi with gain flatness variation of 1.5 dB is achieved. In addition, the front-to-back ratio of the self-packaged antenna array is better than 20 dB.