Dual-Band Patch Antenna for Mobile Phones.
Due to size reduction of the handsets the size of the mobile phone antennas must be kept as small as possible. This example shows simulation results of the dual-band internal shorted patch antenna (PIFA) which go well with reported [1] measurements. The PIFA covers E-GSM900 (880 MHz - 960 MHz), GSM1800 (1710 MHz - 1880 MHz), DECT (1880 MHz - 1900 MHz), PCS1900 (1850 - 1990 MHz), and UMTS (1900 MHz - 2170 MHz) with S11 < - 4 dB and high radiation efficiency. Figure 1 shows the structure of the antenna as created in CST MICROWAVE STUDIO® (CST MWS).
Figure 1: Patch antenna
This antenna consists of three shorted patches, one for the lower band and two for the upper band. The elements were joined together and folded into a meander-shape in order to fit the geometry requirements of a mobile phone. With CST MWS, for example the distribution of electric fields at different frequencies can be studied as shown in Figure 2.
Figure 2: Distribution of electric fields at frequency (a) 926 MHz and (b) 1934 MHz
The simulated S-parameters results are shown in Figure 3 and were obtained in real time via CST MWS"s Discrete Fourier Transform. Only a single run is required to obtain the full range of S-parameters over the desired frequency range.
Figure 3: Reflection coefficient simulated in CST MWS
Farfield patterns at any arbitrary frequencies may be extracted from the Time Domain results via the FFT technique. A polar plot of the farfield at 926MHz is shown in figure 4.
Figure 4: Polar plot of farfield pattern of the PIFA antenna at f = 926MHz
This example has demonstrated the ability of CST MWS to handle this type of antenna. With the comprehensive range of CAD import formats, CST MWS can handle much more complex antennas used in mobile phones. The ability to perform a single simulation also avoids the need to perform several discrete frequency simulations hence allowing a better insight into the broadband behaviour of dual- or multi-band antennas.
References: [1] J. Ollikainen, O. Kivekas, A. Toropainen, P. Vainikainen, "Internal Dual-Band Patch Antenna for Mobile Phones", Millenium Conference on Antennas & Propagation, Davos, April 2000, CD-ROM SP-444
這是 PIFA Antenna:)
圖片出不來(lái)
