A distributed mixer is configured of an artificial transmission line of which an input end is connected to an LO terminal and a terminal end is connected to an IF terminal, an artificial transmission line of which an input end is connected to an RF terminal, FETs that perform frequency synthesis of LO signals and RF signals and that are disposed following the artificial transmission lines and of which gates are connected to the artificial transmission line and sources are grounded, a bias circuit that applies gate bias voltage to a terminal end of the artificial transmission line, a terminating resistor that connects the terminal end of the artificial transmission line and a ground, and a plurality of transmission lines provided between the artificial transmission line and a drain of each FET.

A distributed mixer is configured of an artificial transmission line of which an input end is connected to an LO terminal and a terminal end is connected to an IF terminal, an artificial transmission line of which an input end is connected to an RF terminal, FETs that perform frequency synthesis of LO signals and RF signals and that are disposed following the artificial transmission lines and of which gates are connected to the artificial transmission line and sources are grounded, a bias circuit that applies gate bias voltage to a terminal end of the artificial transmission line, a terminating resistor that connects the terminal end of the artificial transmission line and a ground, and a plurality of transmission lines provided between the artificial transmission line and a drain of each FET.

An RF front-end system is formed to include tunable frequency converters within the transmit and receive sections of each channel, allowing for conventional, limited-bandwidth wireless devices to transmit and receive a broad range of frequencies. Both the transmit and receive sections use superheterodyne frequency conversion to provide the translation between the limited frequency band associated with conventional wireless devices and wide frequency band (e.g., between about 100 MHz and 7000 MHz) approved for wireless communication. By virtue of using a local oscillator that can be widely tuned over the complete available frequency spectrum, the up-converted signals used for transmission can be expanded over this wider frequency selection.

A universal nonlinear variable delay filter includes a first mixer configured to convert an input signal to an up-converted signal including a frequency corresponding to a selected time delay. The input signal includes an original frequency. The variable delay filter also includes a nonlinear filter that filters the up-converted signal and generates a delayed signal that is delayed by the selected time delay. The variable delay filter further includes a second mixer configured to convert the delayed signal to a down-converted signal including a frequency substantially equal to the original frequency.