An enhanced loop in a passive tuner consists of an extremely low loss coupler and a high directivity circulator. In the case of source reflection factor synthesis, a passive loop generates an additional incident traveling wave. This wave, added to the primary incident traveling wave, augments the traveling wave and thus increases the magnitude of the synthesized reflection factor at the source port of a device, such as a transistor. In the case of load reflection factor synthesis, the passive loop augments the initial reflected traveling wave by pumping an additional traveling wave. This additional traveling wave helps in synthesizing a higher load reflection factor at the load port. This architecture is capable of high reflection factor synthesis that enables load synthesis even on the border of the Smith chart. There is no problem of instability with the architecture of the present invention.