II. DESIGN OF DUAL FEED APERTURE
COUPLED ANTENNA
A dual offset microstrip feed line was used to feed the
aperture. Two different layers were used for the microstrip
dual feed lines. The resulting measured impedance
bandwidth was even wider than simple aperture coupled
microstrip antenna [3]. The antenna pattern was measured at
several frequencies over the antenna bandwidth and was
found to have good gain, consistent antenna patterns and
low cross polarization [11]. An aperture coupled wideband
antenna design is modeled on 0.508 mm thick RT Duroid
5880 substrate with r is 2.2. Figure 2.1 shows structure of
proposed antenna and the dimensions are shown in table 1.
Figures 2.2 and 2.3 are shows the measured return loss (The
term “return loss” refers to the negative of the reflection
coefficient in decibels) represented by S22 and VSWR
respectively obtained by simulated with HFSS’11. The
simulation of dual linear polarized presents a bandwidth of
patch antenna is 1.54 GHz. From the results, impedance
band width, defined by the -10 db level of S22 is 14.6%
(9.79-11.33 GHz) for dual feed aperture coupled antenna