Quadband Microstrip Slot Antenna Combined with U- and L-shape Strips for Multiband Body-centric Wireless Applications

This paper proposes a new design of quadband microstrip slot antenna at the frequency of 924 MHz, 1800 MHz, 2450 MHz and 5800 MHz aiming at multiband body-centric wireless applications. The antenna is numerically designed by using CST Microwave Studio based on the Finite Integration Technique (FIT), which is fed by 50\Omega microstrip line feeding technique. The antenna is constructed on a conventional FR4 substrate with the size of 95 mm \times 85 mm \times 1.6 mm. In order to generate multi-resonant frequency, rectangular slots are applied on the patch, which the slots are combination of U- and L-shaped strips. The proposed antenna is then fabricated for basic validation by measuring S- parameters using Vector Network Analyzer. The measurement confirms that the measured results show multiband characteristics at the desired frequencies (quad-bands), those are at 924 MHz, 1800 MHz, 2450 MHz and 5800 MHz, are confirmed. The antenna provides the impedance bandwidth 98 MHz at 924 MHz band, 425 MHz at 1800 MHz band, 135 MHz at 2450 MHz band and 390 MHz at 5800 MHz band. Both of the measured and the simulated S-parameters agree well. In addition the radiation pattern and gain is also measured to confirm the simulation. The results shows agreement with the simulation at each operating band with reasonable obtained gain.