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Filtronic Lx Oy

Petra Ollitervo

Petteri Annamaa

Jyrki Mikkola

Heikki Korva

Kimmo Antila

Matti Niemi

A multiband planar antenna intended for small-sized radio devices and a radio device. The basic structure of the antenna is a two-resonance PFA, the radiating plane () of which has a structural part () corresponding to the lowest operating band and a structural part () corresponding to the upper operating band. In addition, a loop resonator () operating as a radiator is formed in the radiating plane. The ground conductor () of the feed line of the loop is at the same time the short-circuit conductor of the PIFA. The second conductor () of the feed line is connected to the opposite end of the loop, and it operates as the feed conductor of the PIFA. At the same time the structural part () of the radiating plane that corresponds to the lowest operating band is located between the loop and the structural part of the PIFA that corresponds to the upper operating band, in order to reduce interference between them. The resonance frequency of the loop radiator is arranged on the upper operating band of the antenna, for example. Thus the loop improves the matching of the antenna on the upper operating band and the matching and efficiency on the lowest operating band as well. This is based on additional inductance caused by the loop conductor () that functions as a part of the feed conductor of the PIFA.

Multiband planar antenna

A small and foldable radio device antenna and a radio device which has an antenna according to an embodiment of the invention. The radiating element in the antenna is a conductor having an outline shaped substantially like a rectangle and defining a plane which is perpendicular to the ground plane situated on the circuit board of the radio device. The radiating element fits inside the foldable device in the perpendicular position. The element is connected to the radio device only by its feed point. Resonating frequencies of the element can be arranged by shaping the element, and by means of discrete components. The matching of the antenna is arranged by providing an appropriate distance between the radiating element and ground plane. In an operating situation, an antenna gain is achieved which is considerably higher than that of a PIFA of equal height.

Antenna for foldable radio device

Internal planar antenna especially applicable to mobile communication devices. A PIFA-type planar antenna is fed coaxially-like. This means that the feed conductor ( ) of a radiating plane ( ) is surrounded by a shield conductor ( ) galvanically connected to the ground plane (GND) for the length between these planes. The shield conductor at the same time serves as a short circuit conductor for the antenna. The antenna is matched by means of a matching slot ( ) going between the connection points of the feed and short circuit conductors, and/or of the shape of the short circuit conductor. A feed arrangement at issue increases antenna gain without increasing the SAR value of the antenna.

Planar antenna

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London, United Kingdom

Petra Ollitervo