Second harmonic uniplanar active integrated antenna array with strong coupling

In this paper, a new technique to realize a small-sized uniplanar active integrated antenna array using FET's and CPW's is reported. To analyze the entire circuit including the slot input impedance, a large signal analysis was carried out including reactance due to CPW discontinuities. A 4-element array operated at the fundamental frequency of 7.5 GHz and at the second harmonic frequency of 15 GHz. Spatially separated radiation patterns were obtained at each frequency.