Stefan Irmscher

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

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.

Design and development of a multiband loop antenna for cellular mobile handsets

This paper presents the results of the design and characterization of a loop antenna for mobile cellular handsets. Based on a typical smart phone antenna geometry, a bottom mounted off-ground meanderline loop antenna has been designed, which has the potential to cover the required bands of Long Term Evolution (LTE) US 700MHz, Global System for Mobile communications (GSM) 824–960MHz, Digital Communication System (DCS) 1710–1880 MHz, Personal Communication Services PCS 1850–1990 MHz, Universal Mobile Telecommunications System (UMTS) 1920–2170MHz and LTE EU 2500. The carrier volume of 50∗10∗5mm3 and ground plane of length 100mm is used. The carrier permittivity εr is 2.66 and loss tangent tanδ is 0.00629 @2.44GHz. Copper is used as a metal part of the antenna having conductivity of 5.8e7 S/m and thickness of 0.1mm. The antenna supports balanced and unbalanced modes for certain frequencies. It is highly efficient in terms of small volumetric size for a given bandwidth of operations. The antenna generates weak near field electric and magnetic fields complying with the standards for the Specific Absorption Rate (SAR) and Hearing Aid Compability (HAC). The impact of body effects on the radiation efficiency has been quantified. The measured results of the prototype are in good agreement with the simulated results.