High-frequency module

A high-frequency module comprising:

• a substrate;
• a plurality of conductive film patterns that are formed on a front surface of the substrate;
• and
• a bipolar transistor which is mounted on the substrate and has an emitter, a collector, and a base, wherein:
• the plurality of conductive film patterns include:
• a first conductive film pattern which is electrically connected to the base and includes a resonance pattern, the resonance pattern outputting a signal at a frequency in a quasi-millimeter wave band or higher by direct oscillation;
• a second conductive film pattern which is electrically connected to the collector and connected to a power source;
• and
• a third conductive film pattern which is electrically connected to the emitter and includes a grounded filter pattern and a planar open transmission line, the planar open transmission line operating as an antenna capable of transmission and/or reception of the signal at the frequency in the quasi-millimeter wave band or higher and constituting capacitance coupling with the base, wherein:
• the bipolar transistor comprises a first terminal and a second terminal,
• the grounded filter pattern has one end connected to the second terminal of the bipolar transistor, and an open stub is interposed between the second terminal and the grounded filter pattern,
• the planar open transmission line causes capacitance coupling with the first terminal, and
• a portion of the signal transmitted through the open transmission line is fed back to the base via a capacitance produced by an inter-terminal capacitance between the emitter and the base and the capacitance coupling.