“…However, even though these distributed approaches can achieve true time delay along the line sections, their physical sizes make them impractical for integration with multiple arrays in a commercial IC process, especially below K-band ( 30 GHz) frequencies. The migrations from distributed networks to lumped-element configurations, such as synthetic transmission lines with varactors (and/or variable inductors) tuning [10]- [12], lumped hybrid-couplers with reflection loads [13]- [15], or the combined topologies of lumped low-pass filters and high-pass filters [16]- [18], seem to reduce the physical dimensions of the phase shifters with reasonable performance achieved. However, for fine phase quantization levels over wide operation bandwidth, the size of the lumped passive networks grows dramatically, mainly for the various on-chip inductors used, and is not suitable for integrated phased array systems on a chip.…”