Investigations On Microwave And Millimeter Wave Integrated Antennas

With the recent explosion of wireless communication technology, especially personal mobile communication technology, the resource of lower frequency spectrum is almost exhausted. The technology for higher frequency spectrum is a key solution for high speed, wideband wireless communication system. Millimeter wave (mmW) frequency spectrum is defined to be 30-300 GHz, which corresponds to wavelengths from 10 to 1 mm. Because of the feature of short wavelength, wide bandwidth and less interference, millimeter wave technology has attracted more and more attention from both academia and industries. A lot of researches have been done on millimeter wave communication system abroad operating at 20GHz,60GHz and 80GHz, while Q-LINKPAN(IEEE 802.11aj) with a domestic independent intellectual property rights operating at 40.5-50.2 GHz is also proposed. A lot of protocols and products have been done on millimeter wave communication system.The dissertation focuses on the research of antennas applied in millimeter wave applications. Several kinds of antennas have been designed to meet the requirements of various systems. The millimeter wave antennas with the features of minimized, high performance and good integration ability are in great demand. To meet these requirements several kinds of antennas have been proposed. The dissertation is organized as follows:Chapter one proposed a SIW cavity backed rectangular patch antenna. The proposed antenna takes the advantage of the backed-cavity formed by metallic vias and ground to prevent surface wave and increase the gain. The resonant frequency of the backed cavity is close to that of the patch on the top layer, which would increase the impedance bandwidth of the antenna. The proposed antenna is fabricated by standard PCB process, and has the feature of low cost and integration ability.Chapter two proposed a balanced dual fed SIW slot antenna array for Q-LINKPAN point-to-point high gain application. A 16 X 17 array and a 24x25 array are designed and fabricated. The measured gains of the arrays achieve 27.5 dBi and 29.2 dBi respectively. The proposed high gain antenna array is fabricated by standard PCB process, and has the feature of low cost, high gain and integration ability. Because of the balanced dual fed structure, the array has the feature of stable radiation pattern through the operating band, which make it suitable for long distance point-to-point communication system. In order to improve the frequency selectivity, a 3 degree filter and a 5 degree SIW filter are integrated in them without increase the area. After simulation and measurement, the scheme can obviously improve the selectivity of the antenna and VSWR.Chapter three proposed a balanced fed differential SIW slot antenna array for common-mode noise suppression. The electric fields in the SIW in common-mode are different from that in differential-mode. If the slots are designed properly, the array can radiates efficiently in differential-mode, while inefficient in common-mode. It can be used to suppress common-mode noise.Chapter four proposed a cavity-backed magneto-electric dipole antenna and array for Q-LINKPAN. The magneto-electric antenna has the feature of wide band, low back lobe, and equivalent E-plane and H-plane. An I-shaped feed net is used to excite an electric dipole and a magnetic dipole simultaneously. A backed-cavity formed by metallic vias and ground is used to suppress surface wave and increase the gain. The measured impedance bandwidth with |S11|<-15 dB is 15.1%(41.5-48.3 GHz). The gain is larger than 9 dBi in the whole operating band of Q-LINKPAN. In order to increase the gain, a 2x2 array with a common backed cavity and a 2x2 array with 4 individual backed cavities are designed and measured. The impedance bandwidths with |S11|<-15 dB are 18.7%(40.9-49.35 GHz) and 18.4%(40.95-49.25 GHz) respectively. The maximum gains at the normal direction are 14.85 dBi and 14.9 dBi respectively. In the whole operating band of 42-49 GHz, the gain at the normal direction is larger than 14 dBi. The proposed antenna has the feature of wideband, high gain, low cost, and integration ability, which make it suitable for Q-LINKPAN.Chapter five offers a cavity-backed circular-polarized magneto-electric dipole antenna for Q-LINKPAN. Two pairs of rectangular with an angule cut and L-shaped patches are used to realize a magnetic-electric dipole with a wide AR band. The measured bandwidth with |S11|<-15dB is 14.65%(41.7-48.3 GHz). In the operating band of IEEE 802.11aj, the proposed antenna achieves a maximum gain of 8.9 dBic and a minimum gain of 6 dBic. the 3 dB gain bandwidth is 17.5%(14.5-49.5 GHz). The |AR|<3 dB bandwidth is 15.7%(42-48 GHz). Both AR band and impedance band are enhanced. The radiation patterns are stable in a wideband, which meet the require of the Q-LINKPAN.Chapter six presents a dual-polarized stacked patch antenna array with 9 parasitic elements operating at 3.55 GHz for WiMax. The stacked patch increases both impedance bandwidth and gain bandwidth. For the purpose of increase gain,9 parasitic patches are set around. Without increase the complexity of the feed net, both gain bandwidth and VSWR are improved. Both simulation and measurement prove that the proposed structure has the properties of low cost, high gain, wide impedance and gain bandwidths, and suitable for WiMax.