Y-Patch Antenna

Communications technology is constantly aiming to achieve higher signal-to-noise ratios (SNRs) and especially for portable devices a compact design is required. MIMO systems are one way to improve SNR but may require two or more antennas in a single device. In [1] a two-port y-patch is used to achieve dual antenna diversity in a single compact unit. Here a y-patch antenna is modeled in FEKO to determine the isolation between the two ports and radiation patterns of the antenna.

Figure 1 shows the FEKO model of the antenna which consists of a single y-shaped patch with two feed probes. The geometry is symmetric about the y-axis and the probes are attached at equal lengths along the patch. Capacitive loading is used to reduce the inductive impedance of the probes and the structure is mounted on a finite ground plate.

Figure 1: FEKO model of y-patch antenna

Figure 2 shows the surface current distribution at 1800MHz with port 1 active and port 2 terminated in a 50Ω load.

Figure 2: Surface current distribution on y-patch antenna

An S-parameter simulation is used to calculate the input reflection and isolation between the two ports. The results are shown in Figure 3. A -10dB bandwidth of about 6% is obtained and isolation between the two ports are more than 20dB within the operating band.

Figure 3: S-parameters for two-port y-patch antenna

Finally the radiation pattern is calculated with port 1 active and port 2 terminated in a 50Ω load. Figure 4 shows the gain patterns at 1800MHz. The angle phi is measured in the xy-plane from the x-axis.

Figure 4: Radiation patterns for y-patch antenna at 1800MHz

References