Abstract: In accordance with an embodiment, a circuit includes a plurality of filter circuits having a first port, a second port and a third port, where a second port of a first of the plurality of filter circuits is coupled to a first port of a second of the plurality of filter circuits, and each of the plurality of filter circuits includes a first passive filter, a second passive filter, a first coupler and a combining network. The first coupler includes an input port coupled to the first port, an isolated port coupled to the second port, a first phase shifted port coupled to the first passive filter and a second phase shifted port coupled to the second passive filter, and the combining network includes a first input coupled to the first passive filter, a second input coupled to the second passive filter, and an output coupled to the third port.

Abstract: Antenna tuning circuitry includes an antenna tuning node, an antenna tuning switch, and a resonant tuning circuit. The antenna tuning node is coupled to a resonant conduction element of an antenna. The antenna tuning switch and the resonant tuning circuit are coupled in series between the antenna tuning switch and the antenna tuning node, such that the resonant tuning circuit is between the antenna tuning node and the antenna tuning switch. The resonant tuning circuit is configured to resonate at one or more harmonic frequencies generated by the antenna tuning switch such that a high impedance path is formed between the antenna tuning switch and the antenna tuning node at harmonic frequencies generated by the antenna tuning switch. Accordingly, harmonic interference generated by the antenna tuning switch is prevented from reaching the antenna, while simultaneously allowing for tuning of the antenna.

Abstract: According to one embodiment, a communication device is described comprising an antenna, a signal path for supplying a signal to the antenna, two directional couplers arranged within the signal path, wherein each directional coupler is coupled to an adjustable impedance defining the characteristic impedance of the directional coupler, a controller configured to set, for each of a plurality of impedances, the adjustable impedances of the directional couplers to the impedance, a return loss measurement circuit configured to determine, for each of the plurality of impedances, a return loss of the signal path when the adjustable impedances of the directional couplers are set to the impedance and a load impedance determination circuit configured to determine a load impedance of the signal path based on the determined return losses.

Abstract: A resonator element for use in a filter is provided. The resonator element includes a first resonator acoustically coupled to a second resonator. The first resonator has terminals for incorporation in a filter structure. A tuning circuit is coupled to the second resonator to enable tuning of the resonator element.

Abstract: In accordance with an embodiment, an adjustable capacitance circuit comprising a first branch comprising plurality of transistors having load paths coupled in series with a first capacitor. A method of operating the adjustable capacitance circuit includes programming a capacitance by selectively turning-on and turning-off ones of the plurality of transistors, wherein the load path of each transistor of the plurality of transistors is resistive when the transistor is on and is capacitive when the transistor is off.

Abstract: Embodiments of the present disclosure relate to a multi-mode RF system, which is capable of transmitting and receiving RF signals using any of multiple RF communications bands. The multi-mode RF system may integrate RF band specific bandpass filters and low noise amplifiers (LNAs) into a single front-end module, such that each filter and amplifier pair provide selection and gain for at least one RF communications band. Outputs of the LNAs may be combined to provide one or more common signals to a transceiver module, which processes baseband signals associated with the RF communications bands. By integrating the filters and amplifiers into a single module, the filters and amplifiers may be closely coupled to one another, thereby supporting short signal paths between the filters and amplifiers, and having impedances high enough to provide good filter selectivity.

Abstract: A standing wave ratio detection arrangement is disclosed. The arrangement includes a standing wave ratio detector and a controller. The standing wave ratio detector is configured to receive an isolated signal and a coupled signal and to generate a multi-bit return loss signal based on the isolated signal and the coupled signal in the analog domain using successive attenuation of the coupled signal. The controller is configured to determine a standing wave ratio from the return loss and to generate an antenna tuner control signal using the standing wave ratio.

Abstract: In accordance with an embodiment, an adjustable capacitance circuit comprising a first branch comprising plurality of transistors having load paths coupled in series with a first capacitor. A method of operating the adjustable capacitance circuit includes programming a capacitance by selectively turning-on and turning-off ones of the plurality of transistors, wherein the load path of each transistor of the plurality of transistors is resistive when the transistor is on and is capacitive when the transistor is off.

Abstract: A standing wave ratio detection arrangement is disclosed. The arrangement includes a standing wave ratio detector and a controller. The standing wave ratio detector is configured to receive an isolated signal and a coupled signal and to generate a multi-bit return loss signal based on the isolated signal and the coupled signal in the analog domain using successive attenuation of the coupled signal. The controller is configured to determine a standing wave ratio from the return loss and to generate an antenna tuner control signal using the standing wave ratio.

Abstract: The present disclosure relates to de-multiplexing at least one RF input signal feeding RF power amplifier circuitry to create multiple de-multiplexed RF output signals, which may be used to provide RF transmit signals in an RF communications system. Output transformer circuitry is coupled to outputs from the RF power amplifier circuitry to provide the de-multiplexed RF output signals, which may support multiple modes, multiple frequency bands, or both. The de-multiplexed RF output signals may be used in place of RF switching elements in certain embodiments. As a result, RF front-end switching circuitry in the RF communications system may be simplified, thereby reducing insertion losses, reducing costs, reducing size, or any combination thereof. Additionally, the output transformer circuitry may provide load line transformation, output transistor biasing, or both to the RF power amplifier circuitry.

Abstract: In accordance with an embodiment, a circuit includes a plurality of filter circuits having a first port, a second port and a third port, where a second port of a first of the plurality of filter circuits is coupled to a first port of a second of the plurality of filter circuits, and each of the plurality of filter circuits includes a first passive filter, a second passive filter, a first coupler and a combining network. The first coupler includes an input port coupled to the first port, an isolated port coupled to the second port, a first phase shifted port coupled to the first passive filter and a second phase shifted port coupled to the second passive filter, and the combining network includes a first input coupled to the first passive filter, a second input coupled to the second passive filter, and an output coupled to the third port.

Abstract: The present disclosure provides a vertical inductor structure in which the magnetic field is closed such that the magnetic field of the vertical inductor structure is cancelled in the design direction outside the vertical inductor structure, yielding a small, or substantially zero, coupling factor of the vertical inductor structure. In one embodiment, several vertical inductor structures of the present disclosure can be placed in close proximity to create small resonant circuits and filter chains.

Abstract: The disclosure describes a dual hybrid duplexer including two hybrid couplers, two intra-filters, a tunable isolation load, and a phase shifter. The phase shifter may be located at the isolation port. The phase shifter may be located at the antenna port. In one embodiment, a dual hybrid duplexer includes two hybrid couplers, two intra-filters, a tunable isolation load, a first phase shifter located at the isolation port, and a second phase shifter located at the antenna port. The first and second phase shifters have a difference of 90 degrees (plus or minus 10 degrees).

Abstract: This disclosure relates to hybrid couplers for radio frequency (RF) signals. The hybrid coupler includes a first port, a second port, a third port, a fourth port, a first inductive element connected from the first port to the third port, and a second inductive element connected from the second port to the fourth port. The hybrid coupler further includes a first capacitive element and a second capacitive element. The first capacitive element is connected between an intermediary node of the first inductive element and either the first port or the third port, while the second capacitive element is coupled between an intermediary node of the second inductive element and either the second port or the fourth port. Accordingly, the first capacitive element and a portion of the first inductive element and the second capacitive element and a portion of the second capacitive element each form a harmonic trap.

Abstract: Pilot switch circuitry grounds a hot node (an injection node) of a microelectromechanical system (MEMS) switch to reduce or eliminate arcing between a cantilever contact and a terminal contact when the MEMS switch is opened or closed. The pilot switch circuitry grounds the hot node prior to, during, and after the cantilever contact and terminal contact of the MEMS come into contact with one another (when the MEMS switch is closed). Additionally, the pilot switch circuitry grounds the hot node prior to, during, and after the cantilever contact and terminal contact of the MEMS disengage from one another (when the MEMS switch is opened).

Abstract: Radio frequency (RF) front end circuitry includes a notch diplexer. The notch diplexer includes a high pass filter coupled between a high band port and an antenna port, and a low pass notch filter coupled between a low band port and the antenna port. The high pass filter is adapted to receive a high band receive signal having a high band carrier frequency at the antenna port, and pass the high band receive signal to the high band port. The low pass notch filter is adapted to receive a low band transmit signal having a low band carrier frequency at the low band port, and attenuate distortion in the low band transmit signal about a notch stop band before passing the low band transmit signal to the antenna port. According to one embodiment, the notch stop band includes the high band carrier frequency.

Abstract: An adaptive antenna neutralization network (AANN) for neutralizing coupling between a first antenna and a second antenna of a mobile terminal is disclosed. The AANN includes an array of reactive branches. Each of the reactive branches includes a reactive element and an electrically controlled switch with a control input for selectively coupling the reactive element between the first antenna and the second antenna. Also included is a switch driver having an output coupled to the control input of each electrically controlled switch, and a controller having an output for sending control signals to the switch driver to turn on or off individual ones of the electrically controlled switches in response to conditions that indicate a coupling state between the first antenna and the second antenna.

Abstract: RF communications circuitry, which includes a first RF antenna element, a second RF antenna element, a third RF antenna element, and a fourth RF antenna element is disclosed. The first RF antenna element is proximal to the second RF antenna element. The third RF antenna element is proximal to the fourth RF antenna element. A primary axis of the first RF antenna element is about perpendicular to a primary axis of one of the third RF antenna element and the fourth RF antenna element.

Abstract: This disclosure includes embodiments of a tunable hybrid coupler. The tunable hybrid coupler includes a first inductive element having a first inductance, a second inductive element having a second inductance and mutually coupled to the first inductive element, a first variable capacitive element having a first variable capacitance, and a second variable capacitance having a second variable capacitance. The first variable capacitive element is coupled between a first port and a second port. The second variable capacitive element is coupled between a third port and a fourth port. The first inductive element is coupled from the first port to the third port, while the second inductive element is coupled from the second port to the fourth port. Accordingly, the tunable hybrid coupler may form an impedance matching network that is tunable to different radio frequency (RF) communication bands. The tunable hybrid coupler can be used in a tunable RF duplexer.

Abstract: Embodiments of bus interface systems are disclosed. In one embodiment, a bus interface system includes a master bus controller and a slave bus controller coupled along a bus line. The master bus controller is configured to generate an input data signal that is received by the slave bus controller along the bus line. The slave bus controller includes power conversion circuitry configured to convert the input data signal from the master bus controller into a supply voltage. By providing the power conversion circuitry, the slave bus controller is powered using the input data signal and without requiring an additional bus line to transfer a supply voltage to the slave bus controller.