Investigation Of Novel High-Performance Millimeter-Wave Antennas

The shortage of the global bandwidth has motivated the exploration of the millimeter wave(mm-Wave)spectrum,which is still underutilized,for the future broadband communication networks.Although mm-Wave band provides sufficient bandwidth that makes many exciting applications such as the uncompressed high-definition video and ultra-fast file transfer possible,it suffers from considerable loss from rain attenuation and the atmospheric absorption.For example,at 60-GHz frequency band,the excess loss of the channel that is caused by the oxygen absorptionis as high as 15dB/Km.To cope with this problem,antennas at the front-end of the transceiver should feature high gain and many other good performances.Meanwhile,conventional fabrication process in microwave such as PCB cannot satisfy the requirements due to the electrical performance(dielectric constant and loss,etc.)deterioration at high frequency.Therefore,new fabrication technologies,such as LTCC,micro fabrication,3-D printing are exploited to build highly efficient mm-wave devices to meet the requirement of future communications.To this end,several new antenna arrays together with the new fabricating process are designed and investigated in this thesis.The main contents are listed below:1.Novel 60-GHz wideband high gain antenna array for antenna-in-package applications.The novelty of this part focuses on the new antenna radiating element investigation.1)Firstly,based on the concept of planar aperture antenna,single-ended-fed planar aperture antennas(SPAAs)using low-temperature co-fired ceramics(LTCC)process technology are proposed,which not only inherits the merits of the aperture antennas including high gain,wide bandwidth,but also exhibits advantages of low profile and compact size.The aperture is excited by a cross-shaped patch and a loop-shaped balun structure placing below the patch is introduced to convert the single-ended signal into differential one to drive the patch.In this way,the energy can propagate on the patch in a traveling wave form and illuminate the aperture with uniform E-field distributions.Therefore,the antenna achieves good electrical and radiation performances,which are comparable to its balanced-fed counterparts,while processing a simplified structure.The related content entitled "Single-Ended-Fed High-Gain LTCC Planar Aperture Antenna for 60 GHz Antenna-in-Package Applications" has been published on IEEE Transaction on Antennas and Propagation。2)Then,we proposed a low-profile wideband and high gain patch antenna array.We adopt shorting pin connecting the upper patch and ground achieves the function of the virtual ac ground plane of differential feeding.This enables the antenna element to achieve good radiation performances including stable gain,symmetrical beam with low cross-polarization,which are comparable to those of the differential-driven patch antenna while the complex differential feeding network is not required.The related content entitled "Low-Profile Wideband and High Gain LTCC Patch Antenna Array for 60-GHz Applications"has been published on IEEE Transaction on Antennas and Propagation.2.Novel 60-GHz Substrate Integrated Cavity Excited High Gain Antenna Array for 5G mm-Wave communications.The novelty of this part focuses on the new antenna feeding network investigation.1)Substrate integrated cavity excitation approach is proposed and investigated firstly.Instead of the conventional lossy and complicated feed network,the simple but efficient excitation structure based on higher-order-mode(TE340)cavity resonance is used to feed the array.The higher-order-mode cavity feeds all of the radiating elements in the same phase and magnitude,and the resonant mode is excited by a single slot aperture.Based on this new feeding approach,4x4-element linearly and circularly polarized antenna array with high performance is proposed and demonstrated.Compared with antenna arrays that use conventional substrate integrated waveguide feednetwork,the most remarkable advantages of the arrays are their much higher radiation efficiency.Besides,the metallic vias used in the design are also reduced compared with conventional SIW feeding network,which makes the design more cost-effective.More importantly,the proposed array can be extended to larger array design,such as 8x8 and 16×16-element array using even higher resonant modes without sacrifice the radiation efficiency.With these good features,the proposed cavity-backed patch antenna array can be used in the future 60-GHz communication systems.The related contents entitled "60 GHz Wideband High-Gain Circularly Polarized Antenna Array With Substrate Integrated Cavity Excitation" and"mm-Wave High Gain Cavity-Backed Aperture-Coupled Patch Antenna Array," have been published on IEEE Antennas and Wireless Propagation Letters and IEEE Access,respectively.2)By using the substrate integrated magic Tee,we first proposed an array with two dimensional monopulse performances.Compared with their former counterparts,the arrays exhibit merely slight degradation over a much wider bandwidth due to the wide phase/amplitude balance bandwidth that the new feeding network achieved.The related content entitled "60-GHz Substrate Integrated Waveguide Based Monopulse Slot Antenna Arrays" has been published on IEEE Transaction on Antennas and Propagation.3.High-performance 3-D Printed Planar Dielectric Linear-to-Circular Polarization Conversion and Beam Shaping Lenses.The novelty of this part focuses on the new printing technology and new coding units of the lenses/prisms.Firstly,we present a new linear-to-circular polarization(CP)conversion coding unit,based on which two new kinds of beam shaping lenses are proposed.Firstly,under periodic boundary condition,linear-to-circular polarization conversion coding unit is introduced,which not only converts linear polarization to circular one,but also induces required phase delay by adjusting its geometrical parameters.While keeping the polarization characteristic,the phase delay can cover from 0 to 360° and is discretized into 3 bits groups,namely,0°,45°,90°,135°,180°,225°,270°,and 315°(corresponding to the"000","001","010","011","100","101","110",and "111" coding).Then,by properly arranging the coding units,a high gain CP lens is proposed.The lens achieves linear to circular polarization conversion and the beam collimation in the transmission mode simultaneously with a planar configuration,which is different from its former counterparts that placing a lens atop of polarizer.Furthermore,the coding units are used to form Wollaston-prism-like and Rochon-prism-like planar CP beam shaping lenses,which split the beams with different polarizations and the left-hand and right-hand CP beams can be controlled independently.The prototypes working at 30-GHz band are designed,fabricated and measured to verify the idea.The related content entitled "3-D Printed Planar Dielectric Linear-to-Circular Polarization Conversion and Beam Shaping Using Coding Polarizer" has been published on IEEE Transaction on Antennas and Propagation.4.Novel Mm-Wave Polarization Manipulation and Beam Shaping Antennas Based on Phase Modulation Metasurface.1)A new dual-band dual circularly polarized 3-bit beam shaping reflect-arrays for intelligence transportation system(ITS)applications is proposed.By combining the propagation phase and geometrical phase,the deflection angles of the left-hand circularly polarization and right-hand circularly polarized beams are independently manipulated at two different frequency bands,namely 14-GHz for the Ku-band and 26-GHz for the mm-wave band.Two distinct 3-bit coding unit cells,namely,split ring resonators and cross-shaped patches are used for the higher-band and lower band phase tuning,respectively.An FSS is inserted between the two kinds of phasing elements to reduce the mutual coupling between the dual wavelength.Two reflect-array prototypes with different LHCP/RHCP deflecting angles are designed,fabricated and measured to verify the idea.The related content entitled"Polarization-Independent Dual-Band Dual Circularly Polarized 3-Bit Beam Shaping Reflect-Array for Intelligence Transportation System(ITS)Applications”has been submitted to IEEE Transaction on Antennas and Propagation.2)Based on the idea that a linearly polarized antenna array on the polarization rotation ground can achieve circularly polarization,a new dual-band dual circularly polarized(CP)high gain patch antenna array is proposed.The array consists of 16 linearly polarized dual-band elements backed with a new frequency-selective-surface(FSS)-integrated polarization rotation ground.The polarization rotation ground is located underneath the array,which not only acts as a reflector to increase the array boresight gain but also enables the array’s dual CP radiation.The electromagnetic(EM)waves reflected by the ground retard either 90° or 270° with respect to the EM waves of the array directly radiated to the upper sphere at two frequency bands,leading to the dual-band dual CP radiation.With wideband and high polarization purity,the antenna array can be used for the vehicle satellite communication applications.The related content entitled "Dual-Band Dual Circularly Polarized Antenna Array Using FSS-Integrated Polarization Rotation AMC Ground for Vehicle Satellite Communications" has been published on IEEE Transactions on Vehicular Technology.