Fig. 1: Current beamforming network architectures based on OTTDLs.

a Scheme of switched OTTDL with M delay stages. b Classical beamformer based on N identical switched OTTDLs. c Beamformer composed of N OTTDLs with increasing positive delays²⁶. The unit delay value increases one time unit U from one line to another (i.e., from 1U to NU). d Beam patterns generated by the architecture of ref. ²⁶, for 15.8 GHz(red), 16 GHz (blue), and 16.1 GHz (black). In polar coordinates, a superposition effect becomes evident near the broadside region. Upon closer inspection of half of the total angles, the beam squint effect appears for negative pointing angles. e Beam patterns in the architecture of ref. ²⁶, for 14, 12, and 10 GHz. In addition to the beam squint effect observed for negative angles the same angles begin to disappear for lower frequencies.