A linear, low noise, high quality factor (Q) and widely tunable notch filter circuit includes one or more first reactive elements coupled between a first filter node and a first node. The notch filter circuit further includes a multi-branch circuit having multiple parallel branches and coupled between the first node and a second node. Each branch of the multi-branch circuit includes at least a switch coupled to a variable capacitor. A notch frequency of the notch filter circuit is tunable by adjusting a capacitance of the variable capacitor.

A linear, low noise, high quality factor (Q) and widely tunable notch filter circuit includes one or more first reactive elements coupled between a first filter node and a first node. The notch filter circuit further includes a multi-branch circuit having multiple parallel branches and coupled between the first node and a second node. Each branch of the multi-branch circuit includes at least a switch coupled to a variable capacitor. A notch frequency of the notch filter circuit is tunable by adjusting a capacitance of the variable capacitor.

RF transistor amplifiers include an RF transistor amplifier die having a semiconductor layer structure, a coupling element on an upper surface of the semiconductor layer structure, and an interconnect structure on an upper surface of the coupling element so that the RF transistor amplifier die and the interconnect structure are in a stacked arrangement. The coupling element includes a first shielded transmission line structure.

An antenna comprising: a loop made of conductive material; two baluns connected to, and intersecting, opposing sides of the loop, wherein each balun has an output; a 180 hybrid coupler having two input ports, a sum output port, and a delta output port, wherein the two input ports are connected to the outputs of the baluns; a first low noise amplifier (LNA) connected to the sum output port; a second LNA connected to the delta output port; first and second receivers connected to the first and second LNAs respectively; and wherein the antenna is electrically small and is designed to simultaneously receive wideband signals in real time from 3 to 30 MHz.

In some embodiments, an apparatus includes an antenna; a radio-frequency (RF) tuning network configured to receive an input signal via the antenna; an RF energy harvester operatively coupled to the RF tuning network and configured to produce a direct current (DC) output based on the received output of the RF tuning network; and a load manipulator configured to be transitioned between a first configuration and a second configuration to manipulate one or more properties associated with the RF energy harvester such that an input impedance of the RF energy harvester changes from a first input impedance to a second input impedance. The first input impedance is associated with a first distribution of RF energy associated with the input signal relative to the RF energy harvester and the second input impedance is associated with a second distribution of RF energy associated with the input signal relative to the RF energy harvester.

An antenna comprising: a loop made of conductive material; two baluns connected to, and intersecting, opposing sides of the loop, wherein each balun has an output; a 180 hybrid coupler having two input ports, a sum output port, and a delta output port, wherein the two input ports are connected to the outputs of the baluns; a first low noise amplifier (LNA) connected to the sum output port; a second LNA connected to the delta output port; first and second receivers connected to the first and second LNAs respectively; and wherein the antenna is electrically small and is designed to simultaneously receive wideband signals in real time from 3 to 30 MHz.

A method is disclosed of a communication device adapted to process a received signal using either of a first channel selection filter and a second channel selection filter, where the received signal comprises signal entities each representing an individually processed block of data. The method comprises (during use of the first channel selection filter) detecting a presence of an interference signal outside a pass band of the first channel selection filter and switching to use of the second channel selection filter in response to detecting the presence of the interference signal. The method also comprises (if the switching occurs at a first point in time within a first signal entity dividing the first signal entity into a first part and a second part) applying a time domain compensation filter to one of the first part and the second part of the first signal entity. Corresponding frequency computer program product, receiver arrangement and communication device are also disclosed.

A transistor amplifier includes a die comprising a gate terminal, a drain terminal, and a source terminal, a circuitry module on the transistor die and electrically coupled to the gate terminal, the drain terminal, and/or the source terminal, and one or more passive electrical components on a first surface of the circuitry module. The one or more passive electrical components are electrically coupled between the gate terminal and a first lead of the transistor amplifier and/or between the drain terminal and a second lead of the transistor amplifier.