SIW-Based Self-Oscillating Concurrent Dual-Frequency Active Integrated Antenna

In this letter, a self-oscillating concurrent dual-frequency active integrated antenna (DFAIA) is proposed. The proposed circuit is designed based on substrate-integrated waveguide technology, where the concurrent dual-frequency feature is realized by the use of a miniaturized self-oscillating/self-diplexing antenna. The feedback paths on either side of the diplexing antenna, comprising a main port and an auxiliary port, are employed to design the concurrent dual-frequency oscillator. The proposed DFAIA transmits 7.97 and 8.9 GHz signals simultaneously, having effective isotropic radiated power level of 5.3 and 6.41 dBm for the 7.97 and 8.9 GHz signals, respectively. The measured phase noise is approximately -90 and -110 dBc/Hz at 100 kHz and 1MHz offset, respectively for both the lower and the higher frequencies. The overall circuit footprint is 1.33 lambda(g) x 2.26 lambda(g) at the mean frequency of 8.4 GHz.