The push for commercial technologies such as 5G Massive MIMO, and consumer broadband internet via low-earth-orbit satellite, drive a need for low cost phased array antenna technologies. A major obstacle in bringing this technology to market is the cost and complexity of the phased array antenna aperture and the required beamforming or multi-beamforming network. This dissertation presents an efficient, reliable, low-cost and mass-manufacturable multi-beamforming network solution. In accomplishing this, a new class of cavity-based, true-time delay multi-beamformer was devised and investigated. Rotman lens optics are implemented for broadband and low phase-error response. The presented topology offers reduction in size and improvement in efficiency over microstrip based designs, while operating inside a sealed, metal cavity. These characteristics facilitate housing the beamformer within a surface mount package (massive MIMO on a chip). In addition, two related technologies are presented. The first is a single beam scanning architecture based on the the same "massive MIMO on a chip" package, that is capable of scanning the beam over a continuum of angles (no discrete steps). The second is a high-efficiency radial combiner employing a similar port structure to the cavity beamformer. This technology is well-suited as a fixed beam array feed (2D feed), or for feeding rows of an array the scans only in one dimension. Two prototypes have been designed, fabricated, and verified to demonstrate the practical realization of this technology. An SMA connector based design at the UWB frequency band (3.1 to 10.6 GHz) and a second QFN-style surface mount package with design band of 10 to 30 GHz.