Abstract: A loop antenna includes a printed circuit board (PCB), a first antenna structure and a second antenna structure. The PCB includes a first surface and a second surface relative to the first surface, and the PCB includes a clear region and a ground region, wherein the clear region is adjacent to the ground region. The first antenna structure is disposed in the clear region at the first surface. The first antenna structure includes a feed structure and a first ground end. The feed structure is coupled to a power feed end which is disposed in the ground region. The first ground end is coupled to the ground region. The second antenna structure is disposed relative to the first antenna structure at the second surface. The second antenna structure includes a second ground end. The second ground end is coupled to the ground region.

Abstract: A loop antenna includes a printed circuit board (PCB), a first antenna structure and a second antenna structure. The PCB includes a first surface and a second surface relative to the first surface, and the PCB includes a clear region and a ground region, wherein the clear region is adjacent to the ground region. The first antenna structure is disposed in the clear region at the first surface. The first antenna structure includes a feed structure and a first ground end. The feed structure is coupled to a power feed end which is disposed in the ground region. The first ground end is coupled to the ground region. The second antenna structure is disposed relative to the first antenna structure at the second surface. The second antenna structure includes a second ground end. The second ground end is coupled to the ground region.

Abstract: An earphone device including a main body, a speaker, a control element, a pressure sensor, and a touch sensor is provided. The speaker is disposed in the main body for dividing the main body into a front chamber and a rear chamber. The control element is disposed in the rear chamber. The pressure sensor is disposed in the front chamber, is coupled to the control element, is configured to sense a pressure change in the front chamber, and accordingly generates a pressure-sensing signal. The touch sensor is disposed in the rear chamber, is coupled to the control element, is configured to sense a first external touch applied to the main body, and accordingly generates a first trigger-sensing signal. The control element automatically controls an action of the earphone device according to the pressure-sensing signal and the first trigger-sensing signal.

Abstract: A headset apparatus including an audio transmitter, a control circuit, a magnetic field generator and a magnetic field sensor is provided. The control circuit is configured to generate a test signal. The magnetic field generator is coupled to the control circuit to receive the test signal and generate a magnetic field accordingly. The magnetic field sensor is coupled to the control circuit and configured to sense the magnetic field and generate a sensing signal accordingly. When the control circuit detects that the magnetic field is changed based on the sensing signal, the control circuit generates a control signal to enable the audio transmitter.

Abstract: A headset apparatus including an audio transmitter, a control circuit, a magnetic field generator and a magnetic field sensor is provided. The control circuit is configured to generate a test signal. The magnetic field generator is coupled to the control circuit to receive the test signal and generate a magnetic field accordingly. The magnetic field sensor is coupled to the control circuit and configured to sense the magnetic field and generate a sensing signal accordingly. When the control circuit detects that the magnetic field is changed based on the sensing signal, the control circuit generates a control signal to enable the audio transmitter.