The invention relates to a handheld device comprising a first antenna (401, 701, 901, 931, 961, 1101, 1151, 1301, 1501) arranged to operate in at least a first frequency band, and a second antenna (402, 702, 902, 1102, 1302, 1502, 2210) arranged to operate in at least a second frequency band, wherein said second frequency band is different from said first frequency band. According to the invention, the second antenna comprises a slot antenna comprising at least one slot in at least one conductive layer. The invention also relates to enhancement of the isolation between first and second antennas in a handheld device.

Handheld device with two antennas, and method of enhancing the isolation between the antennas

An antenna concept for FM radio reception in mobile phones is proposed and evaluated. By resonating a loop or monopole radiator with a shunt element and connecting the antenna to a high-impedance low noise amplifier, an equivalent antenna efficiency of −24±3 dB is achieved over the entire band of 88 – 108 MHz despite having high-Q gain characteristics and without using control voltages for frequency tuning. Due to the resonant frequency behavior ≫45 dB isolation against co-located transmitting antennas is realized, thereby preventing the amplifier from being saturated during simultaneous operation. A comparison with the hands-free cord and other possible internal solutions is included.

Electrically small receive-only resonant antennas with wideband performance for FM radio reception in mobile phones

This paper presents an analysis of the input impedance and radiation pattern behavior for a rectangular loop antenna when it is reshaped from a narrow square to wide and flat. The antenna operation is examined by 3-D electromagnetic simulations. Parametric simulation results are shown to explain the effect of antenna dimensions on the impedance behavior. Based on the numerical results, an equivalent circuit is developed to model the impedance change due to reshaping the loop antenna. The main observations are that the decreased height and the increased width of the antenna increase the bandwidth potential of the inherently narrowband loop and increase its directivity. These characteristics together with a vertical loop orientation enable a high performance antenna for locations very close to conductive or lossy materials. Based on the presented impedance analysis, an optimized antenna prototype for a wearable use is manufactured and its performance is verified by measurements. Measured radiation efficiency for the antenna in contact with a human tissue phantom is −5.0 dB at 2 GHz and the obtainable bandwidth potential is >10%.

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Analysis of Vertical Loop Antenna and Its Wide and Flat Variant Performance in Wearable Use

A VHF active receiving loop antenna has been designed and tested. The received signal strength is improved by integration of an amplification circuit to an electrically very small loop element. The high gain active loop antenna is applicable in a direction finding array system limited by a physical size constraint. For future work, the active circuitry and the passive loop element would be developed on a single, light weight substrate to achieve a light weight and compact design.

A VHF active receiving loop antenna design

This paper presents the design and implementation of two VHF (30-90 MHz) receiving antennas for direction finding applications. The antennas are constrained to an aperture area of about 15 cm × 15 cm Therefore, an electrically small-loop and dipole antenna elements are considered. Active amplification designs are also proposed to improve the received signal strength. Finally, measurements are conducted to validate the performance of the designs. The measured results also show a good agreement to the simulation results.

Lindberg

Papers

Internal Active Antenna for FM Radio Reception in Mobile Handsets