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Design and Analysis of Wide-Band MIMO Antenna with Diversity and PEG
Published in Leeladhar Malviya, Rajib Kumar Panigrahi, M.V. Kartikeyan, MIMO Antennas for Wireless Communication, 2020
Leeladhar Malviya, Rajib Kumar Panigrahi, M. V. Kartikeyan
Four port MIMO antenna elements are implemented in such a manner that signals can be received in distinct directions. MIMO antenna with pattern diversity and wide-band characteristics is designed using CST simulator, and FR-4 dielectric substrate (thickness of 1.524 mm, permittivity of 4.4, and loss tangent of 0.025) of size 54.82×96.09mm2 is used for fabrication. A combination of triangular and trapezoidal patches, separated by inclined slot of 45° is used to design the MIMO antenna elements. Effect of 45° inclined slot can be accounted on bandwidth extension of the designed antenna [206], and to get distinct field patterns [207].
Frequency domain speech bandwidth extension
Published in Arun Kumar Sinha, John Pradeep Darsy, Computer-Aided Developments: Electronics and Communication, 2019
The majority of the telephone connections are restricted to speech frequencies under 4 kHz called narrowband (NB), causes the characteristic sound of telephony speech. In order to improve the speech quality, speech frequencies up to 7 kHz called wideband (WB) would be desired. The required expensive and time-taking modifications of the today’s telephone network infrastructure turned out, to be a main complication for the introduction of high quality speech transmission in existing networks [1]. An alternative method to enhance the quality of the received NB signal is the artificial bandwidth extension (ABE) [1], where the bandwidth of NB signal is artificially extended. The use of source-filter model divides bandwidth extension (BE) into two subtasks, i.e., excitation signal extension and wideband spectral envelope estimation. Several approaches for excitation signal extension and WB spectral envelope estimation can be found in [2]. Unfortunately, ABE techniques cannot deliver a sufficiently stable WB speech quality under all circumstances [3].
High Frequency Optoacoustic Transducers for Ultrasonic and Photoacoustic Imaging
Published in Lihong V. Wang, Photoacoustic Imaging and Spectroscopy, 2017
Shai Ashkenazi, Yang Hou, Sheng-Wen Huang, Takashi Buma, Matt O’Donnell
The frequency response is measured using a high-frequency (50 MHz) broadband transducer as a test signal source. The frequency response of the test transducer is first evaluated by measuring the pulse-echo off a perfect reflector. The frequency response of the etalon receiver is calculated as: H(f)=P(f)/|TPE(f)|, where P(f) is the power spectrum of the etalon signal and TPE(f) is the pulse-echo response of the test transducer. Details of the frequency response of the three etalons (SU8: 10 μm thick, SU8: 5 μm thick, and PDMS: 3 μm thick) given in Table 18.1 are shown in Figure 18.9. Bandwidth extension is observed as the thickness of the etalon is reduced.
A Multiple-Feedback UWB LNA with Low Noise and Improved Linearity
Published in IETE Journal of Research, 2018
Xin Zhang, Chunhua Wang, Lv Zhao
The simulation results of scattering parameters for this proposed LNA are charted in Figures 5 and 6. The input return loss parameter S11 is an indicator of the input impedance matching performance. Both in the pre-layout and post-layout simulation, the S11 parameters are less than −10 dB from 3.1 to 10.6 GHz. This implies that the multiple-feedback networks adopted in the input stage of this LNA is efficient for bandwidth extension. Moreover, the output return loss parameter S22 is also under −10 dB as well as S11 in the pre-layout simulation. In the post-layout simulation, S22 is a little bigger than −10 dB around 10 GHz. This is caused by the process variation. Acceptable S11 and S22 indicate that this LNA has good input and output impedance matching performance over the whole expected bandwidth.
Design of a slot array antenna with ultra-wideband low-scattering characteristic
Published in Waves in Random and Complex Media, 2023
Liwei Song, Chengxiang Xu, Shuang Chen, Meijun Qu, Jianxun Su
A comparison of the RCS reduction bandwidth between the previous researches on low-scattering slot array antenna and this work is listed in Table 2. Obviously, our work has a great advantage in RCS reduction bandwidth extension, while still maintains the radiation performance of the slot array antenna. Thus, the proposed method of covering the metasurface produces a diffuse scattering pattern that leads to a good performance of the slot array antenna in terms of scattering in ultra-wideband, proving that this method is feasible and practical.
Scanning the Issue
Published in IETE Journal of Research, 2018
The paper on “A multiple-feedback UWB LNA with low noise and improved linearity”, presents the design of a low noise CMOS amplifier with good linearity property for ultra-wide band applications in the 3.1-10.6 GHz band. A multiple-feedback network is designed to provide good bandwidth extension and compact chip size. The design also caters for noise and distortion cancellation in the input stage. The overall amplifier performance is presented in terms of gain, power dissipation, chip size and other specifications in simulation experiments.