An electronic device is provided. The electronic device includes a foldable housing, a flexible display, at least one printed circuit board (PCB), and a wireless communication circuit. The foldable housing includes a hinge structure, a first housing structure connected to the hinge structure and including a first surface facing in a first direction, a second surface facing in a direction opposite to the first direction, and a first lateral member surrounding a first space between the first surface and the second surface, and a second housing structure connected to the hinge structure and including a third surface facing in a second direction, a fourth surface facing in a direction opposite to the second direction, and a second lateral member surrounding a second space between the third surface and the fourth surface.

An antenna module includes a first, a second, a third radiators, and a ground radiator. The first radiator includes a first section and a second section. The second radiator is connected to the first radiator, and includes a third section and a fourth section connected to each other. The fourth section includes a feed end. The third radiator is connected to the third section of the second radiator. The ground radiator is connected to the third radiator. The first, the second, the third, and the ground radiator are sequentially connected in a bent manner to form a stepped shape. The first section of the first radiator and the fourth section of the second radiator jointly resonate at a low frequency band, and the second section of the first radiator, the second radiator, the third radiator, and the ground radiator jointly resonate at a high frequency band.

An antenna structure includes a first radiation element, a second radiation element, a third radiation element, a fourth radiation element, and a dielectric substrate. The first radiation element is coupled to a ground voltage. The first radiation element includes a variable-width portion. The second radiation element has a feeding point. The second radiation element is adjacent to the first radiation element. The third radiation element is coupled to the variable-width portion of the first radiation element. The fourth radiation element is coupled to the second radiation element. The dielectric substrate has a first surface and a second surface which are opposite to each other. The second radiation element and the fourth radiation element are disposed on the first surface of the dielectric substrate. The first radiation element and the third radiation element are disposed on the second surface of the dielectric substrate.

An antenna structure includes a first radiation element, a second radiation element, a third radiation element, a fourth radiation element, and a dielectric substrate. The first radiation element is coupled to a ground voltage. The first radiation element includes a variable-width portion. The second radiation element has a feeding point. The second radiation element is adjacent to the first radiation element. The third radiation element is coupled to the variable-width portion of the first radiation element. The fourth radiation element is coupled to the second radiation element. The dielectric substrate has a first surface and a second surface which are opposite to each other. The second radiation element and the fourth radiation element are disposed on the first surface of the dielectric substrate. The first radiation element and the third radiation element are disposed on the second surface of the dielectric substrate.

A communications device may include an RF device having an operating frequency range, and an antenna coupled to the RF device and being electrically small with respect to the operating frequency range of the RF device. The communications device may include an active capacitor coupled between the RF device and the antenna. The active capacitor may include a settable operating curve with a decreasing capacitance versus increasing frequency over a portion of the operating frequency range of the RF device. The communications device may further include a control circuit coupled to the active capacitor to set the settable operating curve.

A communications device may include an RF device having an operating frequency range, and an antenna coupled to the RF device and being electrically small with respect to the operating frequency range of the RF device. The communications device may include an active capacitor coupled between the RF device and the antenna. The active capacitor may include a settable operating curve with a decreasing capacitance versus increasing frequency over a portion of the operating frequency range of the RF device. The communications device may further include a control circuit coupled to the active capacitor to set the settable operating curve.

A method improves antenna matching for a wireless node, preferably of a sensor wireless node and/or actuator wireless node. A radio signal, or at least a portion thereof, is coupled out of the antenna and/or out of the transmit path of the wireless node. The impedance and/or the resonant frequency of the antenna is determined therefrom in the wireless node, and the impedance and/or the resonant frequency of the antenna is adjusted according to the determined impedance and/or resonant frequency by a circuit acting on the antenna.

A method improves antenna matching for a wireless node, preferably of a sensor wireless node and/or actuator wireless node. A radio signal, or at least a portion thereof, is coupled out of the antenna and/or out of the transmit path of the wireless node. The impedance and/or the resonant frequency of the antenna is determined therefrom in the wireless node, and the impedance and/or the resonant frequency of the antenna is adjusted according to the determined impedance and/or resonant frequency by a circuit acting on the antenna.

A dual antenna with a shared radiator includes a radiator unit, a first feed-in unit, a second feed-in unit, a sensing module and a ground unit. The first feed-in unit and the second feed-in unit are respectively coupled with the radiator unit. The sensing module is connected to a substantial center of the radiator unit and used for sensing a distance between the radiator unit and an external object through the radiator unit. The ground unit is connected to the sensing module. The first feed-in unit is used to send or receive a first radio frequency signal together with the radiator unit, and the second feed-in unit is used to send or receive a second radio frequency signal together with the radiator unit.

A dual antenna with a shared radiator includes a radiator unit, a first feed-in unit, a second feed-in unit, a sensing module and a ground unit. The first feed-in unit and the second feed-in unit are respectively coupled with the radiator unit. The sensing module is connected to a substantial center of the radiator unit and used for sensing a distance between the radiator unit and an external object through the radiator unit. The ground unit is connected to the sensing module. The first feed-in unit is used to send or receive a first radio frequency signal together with the radiator unit, and the second feed-in unit is used to send or receive a second radio frequency signal together with the radiator unit.