Nec Electronics Corporation

Renesas Electronics Corporation

Takao Atsumo

Hiroshi Mizutani

Tatsuya Miya

A switch circuit in which the cut-off characteristic is improved over a wide range of frequencies in the microwave band includes a first field-effect transistor functioning as a switch element, a second field-effect transistor and an inductor. A serially connected circuit composed of the inductor and second field-effect transistor is connected in parallel with the first field-effect transistor across the source and drain thereof. The second field-effect transistor is turned on when the first field-effect transistor operates normally and is turned off when the first field-effect transistor is inspected.

Switchable high pass filter/low pass filter phase shifter having a switch circuit with FETs connected in parallel

Disclosed is a microwave phase shifter including switches each of which utilizes resonance between an off-capacitance of an FET and an inductor connected in parallel with the off-capacitance of the FET, an LPF, and an HPF, a series circuit of an inductor and an MIM capacitor is arranged in parallel with the FET in each portion of the resonance. In a layout of the LC series-connected circuit, though the inductor is of a non-close-packed structure, a metal member or a dielectric material having a relative dielectric constant higher than that of a dielectric substrate is arranged in a free space in a central portion of the inductor.

Phase shifter including a resonant type switch with a free region

A phase shifter selectively switches between a low-pass filterand a high-pass filterusing single pole double throw switchesandprovided on the input and output sides, respectively, and operatively linked to each other. The single pole double throw switchesandinclude FETs Qand Qthat connect single pole side junctions and the low-pass filter, respectively, and inductance circuits (Land R, and Land R) connected in parallel with FETs Qand Q, respectively. The inductance circuits are respectively comprised of the inductor Land the resistor Rconnected in series and of the inductor Land the resistor Rconnected in series.

Growing community of inventors

Kanagawa, Japan

Takao Atsumo