Papers by Keyword: Ka Band

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Authors: Xiao Tian Zheng, Ji Lin Li, Xin Rong Wang
Abstract: The Ka band for satellite communications is allocated from 27GHz to 40GHz and it is possible to realize the high speed data transmission in this 13GHz bandwidth. However, the attenuation especially the rain attenuation is tremendous for the Ka band. And we need to reserve about 4~8dB link budget to guarantee the typical link reliability 99.9% for the constant coding and modulation (CCM). In this paper, we propose a adaptive coding and modulation (ACM) algorithm that can dynamically change the modulation and code efficiency according to link condition. Based on this algorithm we only need reserve about 1dB to realize the 99.7% reliability. The simulation results show that we can derive more than triple throughout compare to CCM.
Authors: Gustavo Guedez, Gao Qiang
Abstract: The progressive congestion of the spectrum at low frequency bands, has obliged the need to use new systems which operate in higher frequencies, such as the Ka bands. The quality and availability of the signals in Ka band are seriously degraded by various climate phenomena, especially in the Amazon area. To keep the link properties in normal conditions (similar to clear sky conditions), is necessary to know the attenuation losses over the service area or footprint. For the Venezuelan Amazon region only Attenuation by atmospheric gases, Attenuation by rain and Scintillation and multipath effects, could be considered according to the ITU. The attenuation calculation is the first step to estimate the link budget and implement any communication service over Ka Band in the Venezuelan Amazon region. The aim of this research is modeling the channel attenuation for Ka band satellite signals and find a suitable attenuation data.
Authors: Anesh K. Sharma, Ashu K. Gautam, D.V.K. Sastry, S.G. Singh
Abstract: This paper presents the design & modeling of distributed MEMS phase shifter for Ka band RF systems. The phase shift can be achieved by periodically placing the MEMS bridge variable capacitors as per Bragg frequency criteria on coplanar waveguide (CPW) using GaAs substrate. The EM & electromechanical simulation are carried out with various structural parameters to optimize the designs. The novelties like low insertion loss, low actuation voltage with distributed actuation pads & separate DC and RF are used to make the design unique. The EM simulations are carried out with HFSS and an insertion loss of -3.49 dB at 36GHz for a total Phase shift of 360 deg. was achieved with return loss of - 20.6 dB over a frequency band 34-38 GHz. The electromechanical simulations are carried to achieve the low actuation voltage of 10.3V. The significance of this study is the realization of the digital phase shifter through DMTL approach.
Authors: Zhong Liang Deng, Yi Dong Yao, Man Zu Hong
Abstract: This letter presents a novel microstrip patch antenna operating in the Ka band (26.5GHz-40GHz) with pattern reconfigurable characteristic. The antenna is provided with one circle patch, two arc patches and four parasitic rectangular patches. The centre patch is connected with the arc patch by a RF MEMS (microelectromechanical systems for RF circuits) switch. The beam can scan in the E-plane by switching the states of the antenna, which is implemented by changing the states of the switches installed in the gap between the patches. Different states of the antenna have different radiation patterns. The two states share the same operating band of 35.6-37.9GHz with the centre frequency of 36.6GHz and their maximum radiation directions are -38° and +37° respectively. The antenna can be applied in radar, satellite, security communications, etc.
Authors: Sheng Li Jia, Bing Liu, Yong Jiu Zhao
Abstract: This paper presents a 35 GHz patch microstrip antenna array on an organic LCP (Liquid Crystal Polymer) substrate. To achieve a higher gain and narrower 3 dB beamwidth, a 4×4 antenna array has been designed and simulated using a 2×2 antenna array as unit array. The results show that an 18.9 dBi of gain and a 3 dB beamwidth of 20.7degrees.
Authors: Shuang Zhao, Le Le Zhang
Abstract: In recent years, with the development of millimeter-wave MMIC chip, millimeter wave technology has been widely used. The millimeter-wave transmitter front-end is designed in this paper. By using second harmonic mixers, we reduce the operating frequency of the oscillator. By using the side exit microstrip - waveguide structure, we strengthen the compact structure. Test results show that the transmitter front-end transmission power is 33dB and its transmission band is 35.5-36GHz.
Authors: Ya Zhou Dong, Shi Wei Dong, Zhong Bo Zhu, Ying Wang
Abstract: This paper presents novel designs of Ka band transitions between standard rectangular waveguide and substrate integrated waveguide (SIW). The proposed transitions can provide simultaneous field and impedance matching. The transition with a height-tapered waveguide exhibits outstanding low-loss performance over an ultra-wideband range (entire Ka-band). And the other one with Chebyshev transformers has a compact profile and low loss better than 2dB in a bandwidth of 11GHz at Ka band. The simulation and analysis of the transitions are carried out with Ansoft HFSS.
Authors: Zhong Liang Deng, Man Zu Hong, Yi Dong Yao
Abstract: A Ka-band microstip patch antenna with the functions of switchable pattern is presented. The antenna structure is composed of three rectangular patches and four radio frequency microelectro-mechanical system (RF MEMS) switches. The switches are placed to connect the center patch with other two ones, with two switches on the top edge of the center patch and others on the bottom edge. By controlling the states of the RF MEMS switches, the proposed antenna can radiate two patterns. Moreover, the switchable functions are operated at the same frequency band with a bandwidth of 30.9%. Simulated results by Ansoft HFSS are given.
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