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Large truncated spherical near-field systems with conductive or absorbing floors are typically used in the measurement of the performances of vehicle-installed antennas. The main advantage of conductive floor systems is the ease of accommodation of the vehicle under test, but their performances are affected by the interaction with the reflecting ground floor. Instead, absorbing-based systems emulating free-space conditions minimize the effect of the interaction with the floor, but generally require longer setup times, especially at lower frequencies (70–400 MHz), where bulky absorbers are typically used to improve reflectivity levels. Considering scaled measurements of a vehicle model, the performances of these two typical implementations are analyzed in the 84–1500 MHz range and compared to free-space measurements. Absorbers with different dimensions and reflectivity have been installed in the scaled measurement setup, and measured data have been investigated with proper post-processing to verify the applicability to realistic systems. Figures of merit of interest for automotive applications, like gain and partial radiated powers, have been compared to free-space to evaluate the impact of different scenarios. [ABSTRACT FROM AUTHOR]

In this paper, a coplanar waveguide (CPW) fed pot‐shaped electronic textile (E‐textile) antenna aided by rectangular ring ground plane has been proposed. The textile patch in pot form is designed by cutting triangular slots on the non‐radiating edges of the rectangular patch, which yields a broadband of 6.45 GHz. The measured antenna impedance bandwidth is from 2.15 to 8.6 GHz with a peak gain of 10.7 dB on fabricated human tissue muscle equivalent phantom model. The proposed antenna exhibits a broadside radiation pattern from 2.15 GHz to less than 6 GHz and conical radiation pattern from 6 GHz to 8.6 GHz covering wide impedance matching bandwidth (S11 ≤ −10 dB) of 120% for dual‐mode off and on‐body communication. In CPW fed technique, the back radiation from the antenna to on body is reduced by using a perfect electric conductor. For wearable applications, considering human safety concern the specific absorption rate levels are maintained, that is less than 1.6 W/kg limit over the operating bandwidth according to IEEE C95.1‐1999 standard averaged over 1 g of tissue model. [ABSTRACT FROM AUTHOR]

Resonances, i.e., extrema of the eigenvalues of characteristic modes for closed perfectly conducting objects are investigated. The characteristic modal solutions based on the electric, magnetic, and combined field integral operators (EFIO, MFIO, and CFIO) are studied and compared with analytical solutions for a sphere. All these formulations are found to capture both external (radiating) and internal (cavity) resonances predicted by the analytical expressions. At the internal resonances, the eigenvalues obtained with the EFIO- and MFIO-based approaches are not correct, and the corresponding modes are nonunique. These solutions also exhibit a strong duality between the electric (TM) and magnetic (TE) type modes. A connection is found between the external and internal resonances and the condition numbers of the matrices. The modal expansion of the CFIO-based solution is correct, even though it also experiences the nonuniqueness of the EFIO- and MFIO-based solutions. [ABSTRACT FROM PUBLISHER]

The article investigates the application of three different ground planes for antenna performance enhancement. They are the conventional perfect electric conductor, the perfect magnetic conductor and their combination. A half-wavelength dipole in free space is considered as the reference case and its performance over these ground planes is investigated and compared.