A C-band high efficiency and high gain two-stage power amplifier based on A1GaN/GaN high electron mobility transistor (HEMT) is designed and measured in this paper. The input and output impedances for the optimum po...A C-band high efficiency and high gain two-stage power amplifier based on A1GaN/GaN high electron mobility transistor (HEMT) is designed and measured in this paper. The input and output impedances for the optimum power-added efficiency (PAE) are determined at the fundamental and 2nd harmonic frequency (f0 and 2f0). The harmonic manipulation networks are designed both in the driver stage and the power stage which manipulate the second harmonic to a very low level within the operating frequency band. Then the inter-stage matching network and the output power combining network are calculated to achieve a low insertion loss. So the PAE and the power gain is greatly improved. In an operation frequency range of 5,4 GHz-5.8 GHz in CW mode, the amplifier delivers a maximum output power of 18.62 W, with a PAE of 55.15 % and an associated power gain of 28.7 dB, which is an outstanding performance.展开更多
In this paper performance of three different designs of a 60 GHz highgain antenna for body-centric communication has been evaluated. The basic structure of the antenna is a slotted patch consisting of a rectangular ri...In this paper performance of three different designs of a 60 GHz highgain antenna for body-centric communication has been evaluated. The basic structure of the antenna is a slotted patch consisting of a rectangular ring radiator withpassive radiators inside. The variation of the design was done by changing theshape of these passive radiators. For free space performance, two types of excitations were used—waveguide port and a coaxial probe. The coaxial probe signifi-cantly improved both the bandwidth and radiation efficiency. The centerfrequency of all the designs was close to 60 GHz with a bandwidth of more than5 GHz. These designs achieved a maximum gain of 8.47 dB, 10 dB, and 9.73 dBwhile the radiation efficiency was around 94%. For body-centric applications,these antennas were simulated at two different distances from a human torsophantom using a coaxial probe. The torso phantom was modeled by taking threelayers of the human body—skin, fat, and muscle. Millimeter waves have lowpenetration depth in the human body as a result antenna performance is lessaffected. A negligible shift of return loss curves was observed. Radiation efficiencies dropped at the closest distance to the phantom and at the furthest distance, theefficiencies increased to free space values. On the three layers human body phantom, all three different antenna designs show directive radiation patterns towards offthe body. All three designs exhibited similar results in terms of center frequency andefficiency but varied slightly by either having better bandwidth or maximum gain.展开更多
The Internet of Radio-Light(IoRL)is a cutting-edge system paradigm to enable seamless 5G service provision in indoor environments,such as homes,hospitals,and museums.The system draws on innovative architectural struct...The Internet of Radio-Light(IoRL)is a cutting-edge system paradigm to enable seamless 5G service provision in indoor environments,such as homes,hospitals,and museums.The system draws on innovative architectural structure that sits on the synergy between the Radio Access Network(RAN)technologies of millimeter Wave communications(mmWave)and Visible Light Communications(VLC)for improving network throughput,latency,and coverage compared to existing efforts.The aim of this paper is to introduce the IoRL system architecture and present the key technologies and techniques utilised at each layer of the system.Special emphasis is given in detailing the IoRL physical layer(Layer 1)and Medium Access Control layer(MAC,Layer 2)by means of describing their unique design characteristics and interfaces as well as the robust IoRL methods of improving the estimation accuracy of user positioning relying on uplink mmWave and downlink VLC measurements.展开更多
We introduce a dual-polarized(DP)Fabry–Perot cavity(FPC)antenna operating at the millimeter-wave(mmWave)frequency band with high-gain and wideband characteristics.A DP feeding source and a partially reflective surfac...We introduce a dual-polarized(DP)Fabry–Perot cavity(FPC)antenna operating at the millimeter-wave(mmWave)frequency band with high-gain and wideband characteristics.A DP feeding source and a partially reflective surface(PRS)integrated with a Fresnel zone lens are suggested to realize dual-polarization wave radiation over a wide impedance bandwidth.The feeding source provides vertical and horizontal polarizations while keeping high isolation between the two polarizations.PRS is used to realize Fabry cavity to produce a directive beam radiation.The integrated Fresnel zone rings are introduced for phase correction,leading to a significant gain enhancement for the antenna.For verification,a 60-GHz FPC antenna prototype with DP radiation is designed and fabricated with measurement results.It consists of a feeding source,a PRS integrated with a Fresnel zone lens,a quasi-curved reflector,and four three-dimensional printed supporters.The results illustrate that the peak gains of vertical and horizontal polarizations are 18.4 and 17.6 dBi,respectively.The impedance matching bandwidth for the two polarizations is 14%.The performance ensures that the proposed DP FPC antenna is a promising candidate for the fifth-generation wireless communication systems in the mmWave band.展开更多
基金Project supported by the National Key Basic Research Program of China(Grant No.2011CBA00606)Program for New Century Excellent Talents in University,China(Grant No.NCET-12-0915)the National Natural Science Foundation of China(Grant No.61334002)
文摘A C-band high efficiency and high gain two-stage power amplifier based on A1GaN/GaN high electron mobility transistor (HEMT) is designed and measured in this paper. The input and output impedances for the optimum power-added efficiency (PAE) are determined at the fundamental and 2nd harmonic frequency (f0 and 2f0). The harmonic manipulation networks are designed both in the driver stage and the power stage which manipulate the second harmonic to a very low level within the operating frequency band. Then the inter-stage matching network and the output power combining network are calculated to achieve a low insertion loss. So the PAE and the power gain is greatly improved. In an operation frequency range of 5,4 GHz-5.8 GHz in CW mode, the amplifier delivers a maximum output power of 18.62 W, with a PAE of 55.15 % and an associated power gain of 28.7 dB, which is an outstanding performance.
文摘In this paper performance of three different designs of a 60 GHz highgain antenna for body-centric communication has been evaluated. The basic structure of the antenna is a slotted patch consisting of a rectangular ring radiator withpassive radiators inside. The variation of the design was done by changing theshape of these passive radiators. For free space performance, two types of excitations were used—waveguide port and a coaxial probe. The coaxial probe signifi-cantly improved both the bandwidth and radiation efficiency. The centerfrequency of all the designs was close to 60 GHz with a bandwidth of more than5 GHz. These designs achieved a maximum gain of 8.47 dB, 10 dB, and 9.73 dBwhile the radiation efficiency was around 94%. For body-centric applications,these antennas were simulated at two different distances from a human torsophantom using a coaxial probe. The torso phantom was modeled by taking threelayers of the human body—skin, fat, and muscle. Millimeter waves have lowpenetration depth in the human body as a result antenna performance is lessaffected. A negligible shift of return loss curves was observed. Radiation efficiencies dropped at the closest distance to the phantom and at the furthest distance, theefficiencies increased to free space values. On the three layers human body phantom, all three different antenna designs show directive radiation patterns towards offthe body. All three designs exhibited similar results in terms of center frequency andefficiency but varied slightly by either having better bandwidth or maximum gain.
基金This work was supported by the National Key R&D Program of China(No.2017YFE011230)the EU Horizon 2020 Project(No.761992).
文摘The Internet of Radio-Light(IoRL)is a cutting-edge system paradigm to enable seamless 5G service provision in indoor environments,such as homes,hospitals,and museums.The system draws on innovative architectural structure that sits on the synergy between the Radio Access Network(RAN)technologies of millimeter Wave communications(mmWave)and Visible Light Communications(VLC)for improving network throughput,latency,and coverage compared to existing efforts.The aim of this paper is to introduce the IoRL system architecture and present the key technologies and techniques utilised at each layer of the system.Special emphasis is given in detailing the IoRL physical layer(Layer 1)and Medium Access Control layer(MAC,Layer 2)by means of describing their unique design characteristics and interfaces as well as the robust IoRL methods of improving the estimation accuracy of user positioning relying on uplink mmWave and downlink VLC measurements.
基金Project supported by the Research Grant Council of the Hong Kong SAR,China(No.CityU11218318)the CityU Strategic Research Grant,China(No.SRG-Fd 7005446)。
文摘We introduce a dual-polarized(DP)Fabry–Perot cavity(FPC)antenna operating at the millimeter-wave(mmWave)frequency band with high-gain and wideband characteristics.A DP feeding source and a partially reflective surface(PRS)integrated with a Fresnel zone lens are suggested to realize dual-polarization wave radiation over a wide impedance bandwidth.The feeding source provides vertical and horizontal polarizations while keeping high isolation between the two polarizations.PRS is used to realize Fabry cavity to produce a directive beam radiation.The integrated Fresnel zone rings are introduced for phase correction,leading to a significant gain enhancement for the antenna.For verification,a 60-GHz FPC antenna prototype with DP radiation is designed and fabricated with measurement results.It consists of a feeding source,a PRS integrated with a Fresnel zone lens,a quasi-curved reflector,and four three-dimensional printed supporters.The results illustrate that the peak gains of vertical and horizontal polarizations are 18.4 and 17.6 dBi,respectively.The impedance matching bandwidth for the two polarizations is 14%.The performance ensures that the proposed DP FPC antenna is a promising candidate for the fifth-generation wireless communication systems in the mmWave band.