US Patent 8400235 Active hybrids for antenna systems

In an exemplary embodiment, a fully monolithic active hybrid architecture can be configured to replace a ring hybrid, magic tee, branchline coupler, or 180° hybrid by providing similar functionality in an integrated monolithic solution. Exemplary embodiments of the active hybrids combine active implementations of power splitters, power combiners, and phase shifting elements in a novel fashion allowing for ultra-compact size and broadband performance. In an exemplary embodiment, the active hybrid replaces the typical hybrid couplers with active splitters and active combiners. Similarly, the delay lines and amplitude adjustment elements are replaced by active vector generators. Vector generators are magnitude and phase control circuits. The active hybrid results in certain advantages including being size independent of the operating frequency, wide frequency range of operation, and RF signals undergo a neutral or slight positive power gain, rather than power losses that occur in the passive prior art systems.