A broadband true-time-delay-based multi-beam array architecture is presented in this paper that is applicable to 1-D and 2-D linear antenna arrays. A 1-D millimeter-wave multi-beam array receiver and a 2-D ultra-wide band multi-beam array receiver have been implemented in 0.13- μm SiGe and a 0.13- μm CMOS technology, respectively. The 1-D millimeter-wave multi-beam array receiver with six antennas and seven beams covers the entire 30-40-GHz instantaneous bandwidth, and achieves 18° spatial resolution and ±54° spatial coverage with 4-mm antenna spacing. The 2-D ultra-wideband multi-beam array receiver with 2 × 2 antennas and 7 × 7 beams covers the 3-15-GHz instantaneous bandwidth, and achieves 10° spatial resolution and ±30° spatial coverage in each dimension with 3-cm antenna spacing.