Beamforming Phased-Array-Fed Lenses With >0.5λ-Spaced Elements

We propose a phased-array-fed lens (PAFL) antenna that is capable of beamforming like a phased array but with array elements spaced beyond 0.5 lambda. The PAFL produces high-quality scanned beams using only five active feeds. This architecture represents dramatic cost and power savings over conventional phased arrays while providing many of the features. We present an optimal beamforming method to achieve the maximum gain at any angle using a subset of feeds and a multiobjective optimizer using particle swarm optimization for more granular pattern control. The method is applied to several simulated state-of-the-art lens antennas with good performance confirming the generality of the method. The theory is demonstrated with a prototype PAFL comprising a 4 inch aperture gradient-index (GRIN) lens antenna, an 8-element 0.725 lambda-spaced linear patch array operating at 29 GHz, and a commercial Ka-band SATCOM beamformer integrated circuit (IC). The prototype achieves the maximum gain at all angles and improves the scan loss by 4 dB at +/- 50..

Automated summary

A phased-array-fed lens (PAFL) antenna is proposed, which can achieve beamforming like a phased array with array elements spaced beyond 0.5 lambda. The PAFL antenna produces high-quality scanned beams using only five active feeds, representing significant cost and power savings compared to conventional phased arrays. An optimal beamforming method and a multiobjective optimizer are presented to achieve maximum gain at any angle by controlling the radiation pattern, demonstrated on several simulated state-of-the-art lens antennas.