Abstract: A hybrid matching network is suitable for use with a radio frequency transmission system having a fundamental frequency and a terminating impedance. The hybrid matching network includes a first port, a first capacitor coupled between the first port and ground and having a self resonance frequency that provides attenuation of at least a first amount of a second harmonic of the fundamental frequency, an inductor coupled between the first port and ground and having an inductance such that a parallel combination of the first capacitor and the inductor has a resonant frequency at the fundamental frequency, a transmission line segment having a first end coupled to the first port, a second end, having a desired physical length and a desired physical width, and a second port coupled to the second end of the transmission line segment and adapted to be coupled to the terminating impedance.

Abstract: In an embodiment, a circuit device for coupling to an antenna includes a first impedance matching circuit configured to couple to the antenna and a second impedance matching circuit configured to couple to the antenna. The circuit device further includes a power amplifier coupled to the first impedance matching circuit and includes a low-noise amplifier coupled to the second impedance matching circuit. Additionally, the circuit device includes a selectable impedance adjustment circuit coupled between the low-noise amplifier and the second impedance matching circuit, which selectable impedance adjustment circuit is configured to selectively adjust an impedance associated with the low-noise amplifier when the power amplifier is transmitting a signal through the antenna.

Abstract: In an embodiment, a circuit device for coupling to an antenna includes a first impedance matching circuit configured to couple to the antenna and a second impedance matching circuit configured to couple to the antenna. The circuit device further includes a power amplifier coupled to the first impedance matching circuit and includes a low-noise amplifier coupled to the second impedance matching circuit. Additionally, the circuit device includes a selectable impedance adjustment circuit coupled between the low-noise amplifier and the second impedance matching circuit, which selectable impedance adjustment circuit is configured to selectively adjust an impedance associated with the low-noise amplifier when the power amplifier is transmitting a signal through the antenna.

Abstract: A filter includes an input and an output. First and second filter stages having respective stage inputs and stage outputs are connected in cascade between the input and the output. Each filter stage includes an amplifier having an amplifier input and an amplifier output and an inner feedback loop connecting the amplifier output to the amplifier input. An outer feedback loop connects the stage output of the second filter stage with the stage input of the first filter stage. The first and second filter stages and the outer feedback loop are arranged so that an s-space closed-loop transfer function of the filter includes two zeros and a single pole.