Abstract:
This report presents the design of four multiband millimeter-wave antennas for wireless communications. The design is performed using Computer Simulation Technology (CST) Microwave Studio tool. The performance of the antennas is evaluated in terms of gain, radiation efficiency, scattering parameter by the variation of antenna length as well width. Different frequencies are applied for the same communication scenario in different countries. Furthermore, different frequencies are used for different applications within a country. Hence, the design of multiband antenna is useful for providing multiple resonance frequencies required for several application scenarios. The current demands for extremely high data rate wireless services and the spectrum scarcity are forcefully motivating the use of the millimeter-wave (mm Wave) frequencies. Two multiband patch antennas and two array antennas operating at millimeter band are proposed in this report. The first one is a quad band antenna with center frequencies of 35.68 GHz, 45.20 GHz, 55.42 GHz, and 80.55 GHz. The antenna is small sized with dimensions of 5.2 mm by 5.5 mm. This antenna is shaped like double F and the overall radiation of the antenna is controlled by the different arms of the individual F patterns. The second one is a penta band array antenna which is designed from the first antenna with center frequencies at 34.77 GHz, 47.23 GHz, 58.43 GHz, 69.63 GHz, and 80.55 GHz to get greater gain and directivity. The size of this antenna is 12.4 mm by 6.5 mm. Then first antenna is modified to get the third antenna to get a higher frequency resonance frequency. This is a penta band antenna with a size of 4.8 mm by 5.4 mm and center frequencies are 35.84 GHz, 46.07 GHz, 56.74 GHz, 81.6 GHz, and 110.09 GHz. The fourth antenna is an array antenna designed from the third antenna which gave nine center frequencies with a size of 11.1 mm by 6.4 mm. The nine center frequencies are 28.03 GHz, 36.5 GHz, 53.11 GHz, 65.98 GHz, 77.64 GHz, 89.3 GHz, 100.52 GHz, 111.74 GHz, and 122.19 GHz. The simulated radiation efficiency of the both single element multiband patch antennas is close to 90% at most resonance frequencies and in the both array antennas, the gain and directivity are high. The performance of the antennas is evaluated in terms of scattering parameter, bandwidth, voltage standing wave ratio, gain, directivity, and radiation efficienc