Abstract: Methods and apparatus for calibration of a second-order input intercept point (IIP2) of a mixer, such as a mixer in a wireless receive chain. One example circuit for mixer IIP2 calibration generally includes a first receive chain comprising a first mixer and a single tone generator having an output coupled to an input of the first mixer and configured to generate a calibration signal having a single baseband tone. One example method of mixer IIP2 calibration generally includes generating a calibration signal comprising a single baseband tone, applying the calibration signal to an input of a mixer, such that the mixer generates a differential tone at an output of the mixer, and adjusting the mixer to minimize a power of the differential tone at the output of the mixer.

Abstract: An example apparatus includes a polyphase transconductance-capacitor filter. The polyphase filter includes a DC bias voltage node, a plus in-phase filter unit, a minus in-phase filter unit, a plus quadrature-phase filter unit, and a minus quadrature-phase filter unit. Each filter unit respectively includes an input node, an output node, and a control node. The polyphase filter also includes a plus in-phase switch and a minus in-phase switch. The plus in-phase switch is coupled to the control node of the plus in-phase filter unit, the DC bias voltage node, and the input node of one or both of the plus quadrature-phase filter unit and the minus quadrature-phase filter unit. The minus in-phase switch is coupled to the control node of the minus in-phase filter unit, the DC bias voltage node, and the input node of one or both of the plus quadrature-phase filter unit and the minus quadrature-phase filter unit.

Abstract: Aspects of the disclosure relate to a radio frequency phase shifter. An example includes an amplification stage to produce an amplified voltage, the amplification stage having a first amplifier with a first input coupled to a first output of a hybrid coupler and a second amplifier with a complementary second input coupled to a complementary second output of the hybrid coupler. A vector modulation stage coupled to the amplification stage receives the amplified voltage and produces a modulated vector, the vector modulation stage has an in-phase section and a quadrature section to control the phase of the modulated vector in response to a phase control signal. A varactor coupled across the first input and the second input of the amplification stage adjusts the capacitance between the first input and the second input in response to a capacitance control signal.

Abstract: An apparatus is disclosed for phase-shifting signals. In example implementations, the apparatus includes a phase shifter. The phase shifter includes a first port, a second port, a vector modulator coupled to the first port, and a signal phase generator. The signal phase generator includes multiple amplifiers coupled between the vector modulator and the second port. The signal phase generator also includes multiple capacitors that couple the multiple amplifiers together to form a loop. Each respective capacitor of the multiple capacitors is coupled between a respective pair of consecutive amplifiers of the multiple amplifiers to form the loop.

Abstract: An example apparatus includes a polyphase transconductance-capacitor filter. The polyphase filter includes a DC bias voltage node, a plus in-phase filter unit, a minus in-phase filter unit, a plus quadrature-phase filter unit, and a minus quadrature-phase filter unit. Each filter unit respectively includes an input node, an output node, and a control node. The polyphase filter also includes a plus in-phase switch and a minus in-phase switch. The plus in-phase switch is coupled to the control node of the plus in-phase filter unit, the DC bias voltage node, and the input node of one or both of the plus quadrature-phase filter unit and the minus quadrature-phase filter unit. The minus in-phase switch is coupled to the control node of the minus in-phase filter unit, the DC bias voltage node, and the input node of one or both of the plus quadrature-phase filter unit and the minus quadrature-phase filter unit.

Abstract: A transformer-based antenna switching network includes a transformer having a secondary winding that extends between a first terminal and a second terminal. The first terminal couples to ground through a first switch and connects to a first antenna. The second terminal couples to ground through a second switch and connects to a second antenna.

Abstract: In certain aspects, a receiver includes first amplifiers, wherein each one of the first amplifiers comprises an input and an output. The receiver also includes second amplifiers, wherein each one of the second amplifiers comprises an input and an output, and the outputs of the second amplifiers are coupled to a combining node. The receiver also includes transmission lines, wherein each one of the transmission lines is coupled between the output of a respective one of the first amplifiers and the input of a respective one of the second amplifiers. The receiver further includes a load coupled to the combining node, and receiver elements, wherein each one of the receiver elements comprises an input and an output, and the output of each one of the receiver elements is coupled to the input of a respective one of the first amplifiers.

Abstract: An apparatus is disclosed for phase-shifting signals with a compensation circuit. In example implementations, an apparatus for phase-shifting signals includes a phase shifter having a first port and a second port. The phase shifter also includes a signal phase generator, a compensation circuit, and a vector modulator. The compensation circuit includes a first capacitor with a first capacitance and a second capacitor with a second capacitance. The first capacitance is different from the second capacitance. The signal phase generator is coupled between the first port and the compensation circuit. The vector modulator is coupled between the compensation circuit and the second port.

Abstract: An apparatus is disclosed for bidirectional variable gain amplification. In an example aspect, an apparatus comprises an antenna element of an antenna array and a wireless transceiver. The wireless transceiver comprises a transmit path coupled to the antenna element, a receive path coupled to the antenna element, and a phase shifter disposed in both the transmit path and the receive path. The phase shifter is configured to operate in an active mode and comprises a first bidirectional variable gain amplifier and a second bidirectional variable gain amplifier.

Abstract: In certain aspects, a receiver includes first amplifiers, wherein each one of the first amplifiers comprises an input and an output. The receiver also includes second amplifiers, wherein each one of the second amplifiers comprises an input and an output, and the outputs of the second amplifiers are coupled to a combining node. The receiver also includes transmission lines, wherein each one of the transmission lines is coupled between the output of a respective one of the first amplifiers and the input of a respective one of the second amplifiers. The receiver further includes a load coupled to the combining node, and receiver elements, wherein each one of the receiver elements comprises an input and an output, and the output of each one of the receiver elements is coupled to the input of a respective one of the first amplifiers.

Abstract: An apparatus is disclosed for phase-shifting signals with a compensation circuit. In example implementations, an apparatus for phase-shifting signals includes a phase shifter having a first port and a second port. The phase shifter also includes a signal phase generator, a compensation circuit, and a vector modulator. The compensation circuit includes a first capacitor with a first capacitance and a second capacitor with a second capacitance. The first capacitance is different from the second capacitance. The signal phase generator is coupled between the first port and the compensation circuit. The vector modulator is coupled between the compensation circuit and the second port.

Abstract: An apparatus is disclosed for phase-shifting signals. In example implementations, the apparatus includes a phase shifter. The phase shifter includes a first port, a second port, a vector modulator coupled to the first port, and a signal phase generator. The signal phase generator includes multiple amplifiers coupled between the vector modulator and the second port. The signal phase generator also includes multiple capacitors that couple the multiple amplifiers together to form a loop. Each respective capacitor of the multiple capacitors is coupled between a respective pair of consecutive amplifiers of the multiple amplifiers to form the loop.

Abstract: A radio frequency (RF) front-end receiver having a passive mixer with feed-forward intermodulation distortion cancellation, or at least reduction. An example receiver generally includes a mixer having differential input terminals and differential output terminals and a baseband filter having inputs coupled to the differential output terminals of the mixer. The receiver also includes common-mode sensing circuitry coupled to the differential input terminals of the mixer and configured to sense a common-mode signal of a first differential signal present at the differential input terminals of the mixer. The receiver further includes a conversion circuit coupled to the common-mode sensing circuitry and configured to convert the common-mode signal to a second differential signal presented to the differential output terminals of the mixer and the inputs of the baseband filter.

Abstract: A transformer-based antenna switching network includes a transformer having a secondary winding that extends between a first terminal and a second terminal. The first terminal couples to ground through a first switch and connects to a first antenna. The second terminal couples to ground through a second switch and connects to a second antenna.

Abstract: An apparatus is disclosed for bidirectional variable gain amplification. In an example aspect, an apparatus comprises an antenna element of an antenna array and a wireless transceiver. The wireless transceiver comprises a transmit path coupled to the antenna element, a receive path coupled to the antenna element, and a phase shifter disposed in both the transmit path and the receive path. The phase shifter is configured to operate in an active mode and comprises a first bidirectional variable gain amplifier and a second bidirectional variable gain amplifier.

Abstract: In certain aspects, a receiver includes first amplifiers, wherein each one of the first amplifiers comprises an input and an output. The receiver also includes second amplifiers, wherein each one of the second amplifiers comprises an input and an output, and the outputs of the second amplifiers are coupled to a combining node. The receiver also includes transmission lines, wherein each one of the transmission lines is coupled between the output of a respective one of the first amplifiers and the input of a respective one of the second amplifiers. The receiver further includes a load coupled to the combining node, and receiver elements, wherein each one of the receiver elements comprises an input and an output, and the output of each one of the receiver elements is coupled to the input of a respective one of the first amplifiers.

Abstract: An apparatus is disclosed for mixing signals with a multi-mode mixer for frequency translation. In example implementations, a multi-mode mixer includes a supply voltage node, a ground node, a first data signal coupler, and a second data signal coupler. The multi-mode mixer also includes a mixer core and a current control switch. The mixer core is coupled between the first data signal coupler and the second data signal coupler. The current control switch is configured to selectively enable or disable flow of a current through the mixer core. The first data signal coupler, the second data signal coupler, the mixer core, and the current control switch are coupled together in series between the supply voltage node and the ground node.

Abstract: The present disclosure provides an apparatus that includes a first mixer circuit configured to convert between an RF signal and an IF signal based at least in part on an local oscillator (LO) signal. The first mixer circuit is electrically coupled to a first node that is configured to receive the LO signal and a first bias voltage, a second node that is configured to receive the RF signal or the IF signal, and a third node that is configured to provide the IF signal or the RF signal. The apparatus further includes a second mixer circuit electrically coupled to a fourth node configured to receive the LO signal and a second bias voltage, the second node, and the third node. The second bias voltage has a voltage level that is offset from the first bias voltage.

Abstract: An RF driver circuit may include a wideband output impedance matching and gain circuit, a wideband input impedance matching and gain circuit, and a summer configured to sum the outputs of the wideband output impedance matching and gain circuit and wideband input impedance matching and gain circuit. The wideband output impedance matching and gain circuit and wideband input impedance matching and gain circuit may collectively provide the gain of the RF driver circuit. The wideband output impedance matching circuit may have a source follower configuration. The wideband input impedance matching circuit may have a common gate configuration. Controllable bias voltages may be used to maintain a constant gain and interface impedances in multiple modes of operation.

Abstract: An apparatus is disclosed for complementary variable gain amplification. In an example aspect, the apparatus includes a variable gain amplifier that includes multiple amplifiers. The multiple amplifiers include at least one first amplifier and at least one second amplifier cascaded together in series. The first amplifier includes a first set of transistors having a first doping type. At least a portion of the first set of transistors is configured to implement a first current mirror. The second amplifier includes a second set of transistors having a second doping type. At least a portion of the second set of transistors is configured to implement a second current mirror. The second current mirror is coupled to the first current mirror.