8(a)) and the fibre matrix of the
FR4 circuits (Fig.
And when filled with
FR4 it operates at dual frequencies 3.25 and 4.84GHz with return loss -19.9307 and -11.8844dB respectively
In the case of
FR4, FR8 and FR8 energy was dissipated due to gradual development of damages in frame joints and by friction along the frame-to-glass contact.
Reference Substrate Patch Bandwidth (MHz) material area ([mm.sup.2]) [6]
FR4 25x 25 300, 500, 700 [24]
FR4 23 x 30 290, 290, 700 [25]
FR4 40 x 50 180, 150, 170 Proposed
FR4 20 x 20 360, 440, 1550 Reference Max gain (dBi) Applications [6] 2.15, 2.47, 4.13 WiMAX/WLAN [24] 2.29, 0.9, 3.45 WiFi/WiMAX/C-band [25] 1.7, 2.3, 4.1 Tri-band wireless Proposed 3.62, 3.67, 5.7 WiMAX/C-band
This study has been performed first by taking RT duroid as substrate and then
FR4 as substrate.
The
FR4 board was replaced by air to simplify the simulation model.
7, the frequency from 0 to 32 GHz is a near-field measurement under a fixed distance of 0.7 mm and a loop length of 1.8 mm in the
FR4 substrate.
In order to demonstrate the effectiveness of applying uniform microstrip asymmetrical coupled lines instead of isolated coupled lines in multi-section Wilkinson power divider for elimination the narrow strip widths, a sample of the power divider with 1 : 2.5 power division and bandwidth of 96% is designed with the
FR4 substrate with a thickness of 1.57 mm and approximate dielectric constant equal to 4.47 Furthermore, the designed power divider has three sections and the coupling coefficients are [c.sub.1] = 0.377, [c.sub.2] = 0.268 and [c.sub.3] = 0.165.
Each of the SAR values presented in the following tables (3-6), consists of three different antenna substrates, namely
FR4, Rogers RO3006 (loss free), and Rogers RO4003 (loss free) with variations of dielectric properties of head.
The radiating patch and the L-shaped feeding strip are printed on two pieces of
FR4 substrates and the substrates are supported by plastic posts which have little influence on antenna's performance.