An apparatus for reducing switching time of RF FET switching devices is described. A FET switch stack includes a stacked arrangement of FET switches and a plurality of gate feed arrangements, each coupled at a different height of the stacked arrangement. A circuital arrangement with a combination of a series RF FET switch and a shunt RF FET switch, each having a stack of FET switches, is also described. The shunt switch has one or more shunt gate feed arrangements with a number of bypass switches that is less than the number of FET switches in the shunt stack.

Systems and methods relating to patch antennas. A patch antenna has a substrate, a resonant metal plate at one side of the substrate, and a ground plane at the other opposite side of the substrate. Two feed pins are used to couple the antenna to other circuitry. The feed pins pass through the substrate and holes in at the ground plane. The feed pins are physically disconnected from both the resonant metal plate and the ground plane. The feed pins are capacitively coupled to the resonant metal plate to provide an electronic connection between other circuitry and the patch antenna.

Systems and methods relating to patch antennas. A patch antenna has a substrate, a resonant metal plate at one side of the substrate, and a ground plane at the other opposite side of the substrate. Two feed pins are used to couple the antenna to other circuitry. The feed pins pass through the substrate and holes in at the ground plane. The feed pins are physically disconnected from both the resonant metal plate and the ground plane. The feed pins are capacitively coupled to the resonant metal plate to provide an electronic connection between other circuitry and the patch antenna.

A first resistor connected in parallel to a semiconductor optical modulator having first ends, the first resistor and first ends connected to a reference potential. A first end of a first transmission line is connected to second ends of the semiconductor optical modulator and the first resistor. A second transmission line is connected in series to the first transmission line and has an impedance lower than that of the first resistor. A first end of the second transmission line is connected to a second end of the first transmission line. A third transmission line is connected in series to the first and second transmission lines and has an end connected to a second end of the second transmission line, and has an impedance equal to that of the first transmission line. A second resistor and a capacitor are connected in series between the third transmission line and the reference potential.

A wireless signal emitter of a tire pressure detector includes a controller, an antenna, and an impedance matching module. The impedance matching module includes an impedance matching circuit and an impedance adjusting circuit. The impedance matching circuit is electrically connected to the controller. The impedance adjusting circuit is electrically connected to the antenna and the impedance matching circuit. The impedance adjusting circuit includes a switching element electrically connected to the controller. When the switching element receives different signals of the controller, the impedance adjusting circuit switches between two different configurations, so that the impedance matching module has two different impedances, thereby the antenna sends two different radio frequency signals to achieve a purpose of a single tire pressure detector suitable for in-car receivers of different frequencies.

A wireless signal emitter of a tire pressure detector includes a controller, an antenna, and an impedance matching module. The impedance matching module includes an impedance matching circuit and an impedance adjusting circuit. The impedance matching circuit is electrically connected to the controller. The impedance adjusting circuit is electrically connected to the antenna and the impedance matching circuit. The impedance adjusting circuit includes a switching element electrically connected to the controller. When the switching element receives different signals of the controller, the impedance adjusting circuit switches between two different configurations, so that the impedance matching module has two different impedances, thereby the antenna sends two different radio frequency signals to achieve a purpose of a single tire pressure detector suitable for in-car receivers of different frequencies.

A method and apparatus for use in a digitally tuning a capacitor in an integrated circuit device is described. A Digitally Tuned Capacitor DTC is described which facilitates digitally controlling capacitance applied between a first and second terminal. In some embodiments, the first terminal comprises an RF+ terminal and the second terminal comprises an RF− terminal. In accordance with some embodiments, the DTCs comprise a plurality of sub-circuits ordered in significance from least significant bit (LSB) to most significant bit (MSB) sub-circuits, wherein the plurality of significant bit sub-circuits are coupled together in parallel, and wherein each sub-circuit has a first node coupled to the first RF terminal, and a second node coupled to the second RF terminal. The DTCs further include an input means for receiving a digital control word, wherein the digital control word comprises bits that are similarly ordered in significance from an LSB to an MSB.

A method and apparatus for use in a digitally tuning a capacitor in an integrated circuit device is described. A Digitally Tuned Capacitor DTC is described which facilitates digitally controlling capacitance applied between a first and second terminal. In some embodiments, the first terminal comprises an RF+ terminal and the second terminal comprises an RF− terminal. In accordance with some embodiments, the DTCs comprise a plurality of sub-circuits ordered in significance from least significant bit (LSB) to most significant bit (MSB) sub-circuits, wherein the plurality of significant bit sub-circuits are coupled together in parallel, and wherein each sub-circuit has a first node coupled to the first RF terminal, and a second node coupled to the second RF terminal. The DTCs further include an input means for receiving a digital control word, wherein the digital control word comprises bits that are similarly ordered in significance from an LSB to an MSB.

In one embodiment, a radio frequency (RF) impedance matching network includes electronically variable capacitors (EVCs), each EVC including discrete capacitors operably coupled in parallel. The discrete capacitors include fine capacitors each having a capacitance value substantially similar to a fine capacitance value, and coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value. The increase of the variable total capacitance of each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in.

In one embodiment, a radio frequency (RF) impedance matching network includes electronically variable capacitors (EVCs), each EVC including discrete capacitors operably coupled in parallel. The discrete capacitors include fine capacitors each having a capacitance value substantially similar to a fine capacitance value, and coarse capacitors each having a capacitance value substantially similar to a coarse capacitance value. The increase of the variable total capacitance of each EVC is achieved by switching in more of the coarse capacitors or more of the fine capacitors than are already switched in without switching out a coarse capacitor that is already switched in.