A circuit (4) for establishing a desired impedance value for a radio antenna (5) comprising a transistor (3) having an input (8) and an output terminal (6), and a printed radio frequency transformer comprising a first (1) and a second inductor (2), both inductors (1, 2) having a coupling factor value, and having a first and a second terminal (11, 12; 21, 22). The first terminal (11) of the first inductor (1) is adapted for connecting a radio antenna (5). The input terminal (8) of the transistor (3) is connected to the second terminal (12) of the first inductor (1), and the output terminal (6) of the transistor (3) is connected to the first terminal (21) of the second inductor (2), so that the desired impedance value (Z.sub.2) at the second terminal (22) of the second inductor (2) is determined by the inductance value of the second inductor (2).

An antenna circuit includes a radiation conductor, a matching circuit disposed between a feeding port in the radiation conductor and a feeder circuit, and a frequency-characteristics adjusting circuit connected between a frequency-characteristics adjustment port in the radiation conductor and a ground and including a variable reactance circuit. The matching circuit includes a first inductance element connected in shunt. The frequency-characteristics adjusting circuit includes a second inductance element. The first inductance element and the second inductance element are magnetically coupled to each other.

An antenna circuit includes a radiation conductor, a matching circuit disposed between a feeding port in the radiation conductor and a feeder circuit, and a frequency-characteristics adjusting circuit connected between a frequency-characteristics adjustment port in the radiation conductor and a ground and including a variable reactance circuit. The matching circuit includes a first inductance element connected in shunt. The frequency-characteristics adjusting circuit includes a second inductance element. The first inductance element and the second inductance element are magnetically coupled to each other.

An automatically tunable mobile antenna is provided with toroidal inductors connected in series between the antenna feed point and a whip and a shunt inductor to ground at the RF input, with the inductors forming an L network impedance matching circuit having values which are in a binary sequence and which are selectively added to impedance match the whip to the output impedance of a transmitter.

An antenna structure of an external antenna device includes an elongated substrate, a grounding segment, an antenna segment, a matching module, and a low-frequency extending segment, the latter four of which are disposed on the substrate. The grounding segment and the low-frequency extending segment are respectively arranged on two opposite sides of the antenna segment. The antenna segment includes a feeding portion, a high-frequency portion, and a low-frequency portion. The high-frequency portion and the low-frequency portion are electrically connected to the feeding portion and the grounding segment via the matching module. The low-frequency portion and the low-frequency extending segment each has a signal path, and a total length of the two signal paths is 0.3750.625 times of a wavelength corresponding to a center frequency of a low-frequency band. The low-frequency extending segment is arranged apart from and is electrically coupled to the low-frequency portion.

An electronic device according to an embodiment comprises: a housing which includes a first conductive portion disposed at a first edge, a second conductive portion disposed at the first edge and a second edge perpendicular to the first edge, and a third conductive portion disposed at the second edge; a feeder which feeds power to a feeding point disposed in at least one of the first conductive portion and the second conductive portion; a connection element which can electrically connect the first conductive portion, the second conductive portion, and the third conductive portion to each other; and a processor. A first electrical path from the feeding point to one position of the first conductive portion may be different from a second electrical path from the feeding point to one position of the third conductive portion.

An electronic device according to an embodiment comprises: a housing which includes a first conductive portion disposed at a first edge, a second conductive portion disposed at the first edge and a second edge perpendicular to the first edge, and a third conductive portion disposed at the second edge; a feeder which feeds power to a feeding point disposed in at least one of the first conductive portion and the second conductive portion; a connection element which can electrically connect the first conductive portion, the second conductive portion, and the third conductive portion to each other; and a processor. A first electrical path from the feeding point to one position of the first conductive portion may be different from a second electrical path from the feeding point to one position of the third conductive portion.

Disclosed is an electronic device. The electronic device according to an embodiment includes an antenna element including at least a portion of a housing of the electronic device and configured to resonate in a first frequency band, a conductive plate electrically connected with the antenna element, positioned within the housing, and configured to resonate in the first frequency band or in a second frequency band higher than the first frequency band, a filter circuit electrically connected with the conductive plate and having a pass band in the second frequency band, and a conductive member electrically connected with the conductive plate through the filter circuit and configured to resonate in the second frequency band. Moreover, various embodiment found through the disclosure are possible.

Disclosed is an electronic device. The electronic device according to an embodiment includes an antenna element including at least a portion of a housing of the electronic device and configured to resonate in a first frequency band, a conductive plate electrically connected with the antenna element, positioned within the housing, and configured to resonate in the first frequency band or in a second frequency band higher than the first frequency band, a filter circuit electrically connected with the conductive plate and having a pass band in the second frequency band, and a conductive member electrically connected with the conductive plate through the filter circuit and configured to resonate in the second frequency band. Moreover, various embodiment found through the disclosure are possible.

An electronic device includes: a side member forming sides of the electronic device, the side member including a first conductive portion, a second conductive portion, a first non-conductive portion, and a slit; a printed circuit board including the ground; and a wireless communication circuit, wherein the first conductive portion includes a first electrical path and a second electrical path, the second conductive portion includes a third electrical path and a fourth electrical path, a capacitor is arranged along the third electrical path, and the wireless communication circuit may feed, to the first conductive portion via the first electrical path, an RF signal of a first frequency band and may feed, to the second conductive portion via the third electrical path, an RF signal of a second frequency band which at least partially overlaps the first frequency band.