2022/2
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- ItemObject Tracking Based Surgical Incision Region Encoding using Scalable High Efficiency Video Coding for Surgical Telementoring Applications(Společnost pro radioelektronické inženýrství, 2022-05) Sanagavarapu, Karthik Sairam; Pullakandam, MuralidharSurgical telementoring is an advanced tele-medicine concept where the expert surgeon guides the onsite novice present at the remote location. The efficient telementoring system requires the wireless transmission of high-quality surgical video with less bitrate in less time. The bit rate of the surgical video can be decreased by segmenting the surgical incision region and removing the background region. The High Efficiency Video Coding (HEVC) standard has provided promising results for surgical telementoring applications. But the Rate-Distortion Optimization (RDO) search process in HEVC increases the complexity that in turn increases the encoding time. We propose the method which involves the segmentation of the surgical incision region using the Kernelized Correlation Filter (KCF) object tracking technique. The segmented region is encoded by the complexity-efficient Scalable HEVC (SHVC) to meet the resolution of an end-user device. The complexity of SHVC is decreased by using the Convolutional Neural Network (CNN) and Long- and Short- Term Memory (LSTM) to predict the Coding Tree Unit (CTU) structure. The results show that the proposed method decreases the bitrate significantly for segmented surgical video sequences without degradation in Peak Signal-to-Noise Ratio (PSNR). These results are obtained for the surgical video sequences with slow-moving objects. Furthermore, the CNN+LSTM approach reduces the encoding time of standard SHVC by 51% with negligible Rate-Distortion (RD) performance loss.
- ItemGain and Bandwidth Enhancement of a Metamaterial Loaded Antipodal Vivaldi Antenna Fed by Substrate Integrated Waveguide(Společnost pro radioelektronické inženýrství, 2022-05) Bordbar, Arman; Mohajeri, Farzad; Ghorbani, ZahraThis paper proposes a novel wideband, high-gain, compact Vivaldi antenna operating in the 14.7-20.5 GHz frequency range, where the antenna is fed by the substrate integrated waveguide (SIW). A Negative Index Metamaterial (NIM) has been designed, with its parameters extracted using MATLAB software. The NIM was developed to address the deficiencies of conventional Antipodal Vivaldi antennas. With a measured gain of over 5.3 dBi, the fabricated antenna performs satisfactorily across the entire bandwidth. Due to its low profile and short transversal dimension, the proposed antenna is suitable for antenna arrays; consequently, the proposed antenna design could be a viable option for modern communication and radar systems.
- ItemA Wideband Wearable Antenna with AMC Ground Plane for WBAN Applications(Společnost pro radioelektronické inženýrství, 2022-05) Bhattacharjee, Shankar; Midya, Manas; Bhadra Chaudhuri, Sekhar Ranjan; Mitra, MonojitA flexible wearable antenna with wideband characteristics and having a conical radiation pattern which is suitable for ON body application is presented. To realize a compact antenna size, characteristic modal (CM) analysis is performed initially, and the ground plane of the antenna is utilized to generate one of the resonant modes. The quasi-current loop in the feed layer patch is used to generate another resonant mode. Combination of these two modes has resulted in the wideband performance of the antenna from 4.72 to 6.08 GHz. A planar wideband artificial magnetic conductor (AMC) is used beneath the antenna. This AMC surface compensates the undesired coupling taking place due to the ground radiator thereby reducing the specific absorption rate (SAR) to 76.4% and enhancing the gain of the antenna. The performance of the antenna in terms of return loss, gain, efficiency, SAR and bending sensitivity is studied.
- ItemDesign of h¯-CPM-LFM Radar-Communication Integration Signal(Společnost pro radioelektronické inženýrství, 2022-05) Ye, Mingkun; Tang, Jun; Zhao, Yang; Su, RongqingIn light of the increasing requirement for the electromagnetic spectrum, the integration of radar and communication is widely concerned because of its equipment miniaturizing and high efficiency of spectrum. To address the issue that the communication information in integrated signals for radar and communication affects detection performance, A novel integrated signal is proposed in this paper. Inspired by the high communication efficiency of shaped octal phase-shift keying (S8PSK) and high spectral efficiency of the three-section integrated waveform k-LFM-CPM, we generate a new type of modulation ℎ¯-CPM by the introduction of a precoding method with low complexity and a time-varying modulation index h, h-CPM is used to encode communication data into LFM radar waveform to form a novel radar and communication integration waveform ℎ¯-CPM-LFM. Numerical results show that the designed waveform is at least 10 dB less spectrum extension than other integration waveforms when carrying large amounts of communication information and has excellent BER performance under the condition of strong out-of-band interference. Ambiguity function analysis shows that the waveform has excellent detection performance comparable to LFM.
- ItemA Simple Approach for Improving Bandwidth and Isolation of Wilkinson Power Divider(Společnost pro radioelektronické inženýrství, 2022-05) Nguyen Minh Giang; Luong Duy ManhA simple approach to improve both the bandwidth and isolation of the Wilkinson power divider for using in L-band satellite communications is presented in this paper. To enhance the bandwidth, a multi-section method based on the Chebychev impedance transformation is employed. In order to improve the isolation performance between output ports, the values of isolation resistors are carefully determined by using the iterative approximation method combined with an investigation procedure. In order to validate the proposed design, a two-way and eight-way power divider prototypes were fabricated and tested on a Rogers RO4003C material. Good agreements between simulations and measurements are obtained in a frequency range from 0.8 GHz to 2.2 GHz. The two-way power divider had a fractional bandwidth of 106% with an isolation of better than 30 dB. The eight-way power divider achieved the bandwidth and isolation of 109% and better than 24 dB, respectively. Both the power dividers exhibit the phase imbalance of less than 3 degrees, and amplitude imbalance of less than 0.02 dB. Compared with the other works, the proposed power dividers deliver broader bandwidth and improved isolation while still retaining good insertion loss, low phase and amplitude imbalance in the operation frequency range.