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.

An improved transformer based switch for PALNA applications. The transformer based switch having an input single pole port and a circuit with at least one transformer and at least one switch configured to connect portions of the transformer to ground or to short the transformer. The primary side of the transformer being connected to the input port and the secondary side of the transformer being connected to an output port.

An on-chip transformer circuit is disclosed. The on-chip transformer circuit comprises a primary winding circuit comprising at least one turn of a primary conductive winding arranged as a first N-sided polygon in a first dielectric layer of a substrate; and a secondary winding circuit comprising at least one turn of a secondary conductive winding arranged as a second N-sided polygon in a second, different, dielectric layer of the substrate. In some embodiments, the primary winding circuit and the secondary winding circuit are arranged to overlap one another at predetermined locations along the primary conductive winding and the secondary conductive winding, wherein the predetermined locations comprise a number of locations less than all locations along the primary conductive winding and the secondary conductive winding.

In accordance with an embodiment, a method for operating a millimeter-wave power amplifier including an input transistor having an output node coupled to a load path of a cascode transistor includes: receiving a millimeter-wave transmit signal at a control node of the input transistor; amplifying the millimeter-wave transmit signal to form an output signal; providing the output signal to a load coupled to an output node of the cascode transistor; and adjusting a first DC bias current of the input transistor to form a substantially constant second DC bias current of the cascode transistor.

Certain aspects of the present disclosure generally relate to an amplifier configured to process signals received in different frequency bands, where at least a portion of the amplifier is shared between different modes corresponding to the different frequency bands. One example circuit generally includes an amplifier having at least one first transistor configured to amplify a first signal received in a first mode of operation (e.g., associated with a particular frequency band), and at least one second transistor configured to amplify a second signal received in a second mode of operation. The amplifier may also include a transformer comprising a primary winding and a secondary winding, and one or more switches configured to selectively couple the primary winding to the first transistor or the second transistor based on the first mode or the second mode of operation, respectively. In certain aspects, the transformer may be coupled to a transconductance circuit.

A power amplifier arrangement comprises a power amplifier comprising at least one transistor having a first gate and a second gate. The first gate is configured to receive a radio frequency input signal superimposed with a first control signal, and the second gate is configured to receive a second control signal. The first control signal is a linearization signal varying in relation to an envelope of the input signal and the second control signal is a temperature compensation signal varying in relation to a temperature of the power amplifier, or vice versa.

A radio circuit, comprises an antenna; a differential power amplifier, comprising differential transmit inputs and differential transmit outputs, configured to amplify differential transmit signals received via the differential transmit inputs and output the amplified differential transmit signals via the differential transmit outputs; a differential low noise amplifier, comprising differential receive inputs and differential receive outputs, configured to receive differential receive signals via the differential receive inputs and output amplified differential receive signals via the differential receive outputs; and a transformer comprising a primary winding and a secondary winding, the primary winding coupled with the differential transmit outputs of the power amplifier and the differential receive inputs of the low noise amplifier and the secondary winding coupled with the antenna.

An on-chip transformer circuit is disclosed. The on-chip transformer circuit comprises a primary winding circuit comprising at least one turn of a primary conductive winding arranged as a first N-sided polygon in a first dielectric layer of a substrate; and a secondary winding circuit comprising at least one turn of a secondary conductive winding arranged as a second N-sided polygon in a second, different, dielectric layer of the substrate. In some embodiments, the primary winding circuit and the secondary winding circuit are arranged to overlap one another at predetermined locations along the primary conductive winding and the secondary conductive winding, wherein the predetermined locations comprise a number of locations less than all locations along the primary conductive winding and the secondary conductive winding.

A transformer includes multiple differential ports and first and second transformer windings. The first transformer winding includes a first transformer half-winding coupled to a first differential port of the differential ports. The first transformer winding also includes a second transformer half-winding coupled to a second differential port of the differential ports. An amplifier system that has a transformer is also provided. The amplifier system includes a first and a second stage amplifier. The first stage amplifier includes a first and a second amplifier. The second stage amplifier includes a third and a fourth amplifier. The transformer is coupled between the first stage amplifier and the second stage amplifier, where the transformer has a primary loop and a secondary loop. The primary loop of the transformer may be configured to receive differential signals of the first amplifier. A method for fabricating a transformer is also provided.

A dual mode notch filter for use in a multi-band millimeter wave (mmW) transmitter includes a transmit filter circuit disposed between two amplifiers in a mmW transmit signal path, the transmit filter circuit formed by at least one switch, at least one capacitor, and a double-tuned transformer, the transmit filter circuit having at least two modes configured to selectively filter a spurious signal in at least a first communication band.