A novel two-beam scanning active leaky-wave antenna

Abstract

A novel two-beam scanning active leaky-wave antenna (LWA) has been developed, This LWA with a two-terminal feeding microstrip line structure is integrated with a varactor-tuned X-band high-electron mobility transistor (HEMT) voltage-controlled oscillator (VCO). The signal of the VCO is injected via a T-divider into the radiating element. To excite the first higher order mode, the designed antenna is fed asymmetrically at both ends of the microstrip line. Compared with single-terminal feeding leaky-wave antennas, this configuration offers the advantages of dual-direction and suppression of the reflected wave caused by the open end of the radiating element. The scanning angle is steered over a range of 24-46 degrees for the right beam and 128-150 degrees for the left beam. The Effective isotropic radiated power (EIRP) is calculated to be 17.5 and 16.67 dBm at 10.4 GHz, respectively. The measured return loss S-11 is less than -10 dB in the range of 9-11.5 GHz, The transmission coefficient S-21 indicates that the power radiates into the space.