Abstract: A communication device includes a circuit board having an upper surface and a lower surface, an upper housing disposed on the upper surface, and a lower housing disposed on the lower surface. The circuit board includes a top metal frame disposed on the upper surface, wherein the top metal frame defines a top cavity; a bottom metal frame disposed on the bottom surface, wherein the bottom metal frame defines a bottom cavity corresponding to the top cavity; a microstrip line disposed on the upper surface and extending into the top cavity; and a side coupler disposed on the lower surface and extending into the bottom cavity. The upper housing includes a depression corresponding to the top cavity, and the lower housing includes an aperture corresponding to the bottom cavity.

Abstract: A communication device includes a circuit board having an upper surface and a lower surface, an upper housing disposed on the upper surface, and a lower housing disposed on the lower surface. The circuit board includes a top metal frame disposed on the upper surface, wherein the top metal frame defines a top cavity; a bottom metal frame disposed on the bottom surface, wherein the bottom metal frame defines a bottom cavity corresponding to the top cavity; a microstrip line disposed on the upper surface and extending into the top cavity; and a side coupler disposed on the lower surface and extending into the bottom cavity. The upper housing includes a depression corresponding to the top cavity, and the lower housing includes an aperture corresponding to the bottom cavity.

Abstract: A band-pass filter comprises a first resonator, a second resonator and a third resonator. The second resonator is magnetically coupled to the first resonator. The third resonator is magnetically coupled to the second resonator and is electrically coupled to the first resonator. In addition, the first resonator is a quarter wavelength resonator, the second resonator is a half wavelength resonator, and the third resonator is a quarter wavelength resonator.

Abstract: A transceiver for radio-frequency communication comprises a waveguide, a transmitting port, a receiving port and a receiver load termination. The waveguide receives and transmits radio-frequency signals. The transmitting port is connected to the waveguide and transmits the radio-frequency signals to the waveguide. The receiving port is connected to the waveguide and receives the radio-frequency signals from the waveguide. The receiver load termination is connected to the waveguide and removes the vertical polarization components of the receiving radio-frequency signals. The receiver load termination includes a filtering unit to reduce the energy of the transmitting radio-frequency signals entering the receiver load termination.

Abstract: A waveguide, configured to attach with a printed circuit board, includes a body, a waveguide channel, at least one flange portion, and a plurality of protrusions. The waveguide channel is formed through the body. The at least one flange portion is connected with an end portion of the body. The plurality of protrusions are disposed on a surface of the at least one flange portion and a surface of the end portion and abut against the surface of the printed circuit board.

Abstract: A transceiver for radio-frequency communication comprises a waveguide, a transmitting port, a receiving port and a receiver load termination. The waveguide receives and transmits radio-frequency signals. The transmitting port is connected to the waveguide and transmits the radio-frequency signals to the waveguide. The receiving port is connected to the waveguide and receives the radio-frequency signals from the waveguide. The receiver load termination is connected to the waveguide and removes the vertical polarization components of the receiving radio-frequency signals. The receiver load termination includes a filtering unit to reduce the energy of the transmitting radio-frequency signals entering the receiver load termination.