US 10,476,535 B2 · High-frequency front end circuit and communication apparatus

Abstract

A high-frequency front end circuit includes a frequency fixed filter and frequency variable LC filters, and these are connected in series in a signal transmission path. The frequency fixed filter transmits high-frequency signals in a frequency band of a communication band and attenuates high-frequency signals outside the frequency band of the communication band. One of the frequency variable LC filters is an LC filter and attenuates unnecessary wave frequencies in the frequency band of the communication band. Another one of the frequency variable filters is a resonator filter that passes high-frequency signals in a frequency band of a selected channel and attenuates high-frequency signals in frequency bands of adjacent communication channels of the selected channel.

Claims17

Dependent claims

A high-frequency front end circuit for wireless communication in a usage channel selected from vacant channels, the usage channel and the vacant channels being among a plurality of communication channels in a frequency band used in a wireless communication system, the circuit comprising:

a fixed filter configured to attenuate a high-frequency signal outside the frequency band;
and
a variable filter configured to attenuate a high-frequency signal in the frequency band but of a communication channel other than the usage channel, the communication channel other than the usage channel varying in accordance with selection of the usage channel,
wherein the fixed filter is a frequency fixed-type LC filter and the variable filter is a frequency variable-type elastic wave resonator filter.

1 more element

Dependencies are inferred from the claim text.

High-frequency front end circuit and communication apparatus

Life of this patent

High-frequency front end circuit and communication apparatus

Life of this patent

Abstract

Claims17