Design and analysis of circular microstrip patch probe array for precise specific absorption rate measurement at quad-band

This paper distinguishes the design and analysis of 3 x 2 circular microstrip patch probe array for specific absorption rate (SAR) measurement at quad-band. This novel approach consists of FR4 substrate radial dimension of 88 mm and it has six circular array elements with a radius of 17 mm; out of these six elements, three array elements are having rectangular slots with dimensions of 1.8 x 1.5 x 1.5 mm(3). The array elements are coupled with six probes which have a dimension of 100 mm with a 2.5 mm tip radius; these six probes are embedded into a tissue-equivalent liquid-filled human head mannequin. In this mannequin, instantaneous SAR at any six positions has been investigated. The proposed design resonates at 1.8, 2.1, 2.4, and 2.5 GHz with a return loss of -11.53, -15.90, -15.73, and -25.49 dB. The circular microstrip probe array is fed by a 50 Ohm coaxial feed. In addition, the 3D human head model analysis is also presented. The precisely estimated SAR values are 0.135, 0.108, 0.167, and 0.244 W/kg at 1 g of tissue. For the traceable measurements, each source of uncertainty budget has been estimated.