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In this paper, we propose a propagating path identification method using Finite-Difference Time-Domain (FDTD) method and compressive sensing. In this study, Yee cells are regarded as array antenna, and the compressive sensing is introduced to identify direction-of-arrival of the radio waves. In this method, the signal is alternately transmitted between two antennas, and the DOAs are estimated for...
This paper proposes the evaluation of the multiple-input multiple-output (MIMO) channel capacity using the theory of characteristic modes (TCM) analysis. First, the mode directivity of the ground plate of a small terminal is analyzed by using TCM. MIMO propagation characteristics are evaluated using the ray tracing method. After that, the channel capacity is calculated using the MIMO propagation characteristics...
This paper proposes a propagation path identification method by combining Finite-Difference Time-Domain (FDTD) method and compressive sensing. By regarding a number of Yee cells as a plane array antenna, compressive sensing can be applied to estimate the direction-of-arrival (DOA) of the radio wave in FDTD method. In this method, the signal is transmitted backward and forward between two TRx antennas,...
In this paper, the performance of the passive MIMO transmission with a large number of antennas is experimentally evaluated. The measurement is carried out in an indoor environment, and it is found that the high transmission rate, 2.4 Mbits/s, was attained by using 12 × 12 passive MIMO array.
This paper presents direction of departure (DOD)-based localization technique suitable for indoor environment. Localization is performed by estimating direction from known multiple beacons, where each of them comprises two antennas and 180° hybrid. DOD estimation is performed only from received signal strength indicator (RSSI), which does not have phase information. Indoor measurement campaign has...
For multiple-input multiple-output (MIMO) antenna evaluation, over-the-air (OTA) performance testing is commonly conducted using fading emulator and reverberation chamber. However, such conventional approaches require huge and expensive measurement setups, and therefore, the simplification of the evaluating system configuration is a key challenge. In this paper, we propose a novel channel capacity...
This paper presents the direction estimation technique of RFID, which is aimed to be used for gesture recognition. This technique uses back-scattered signal from passive RFID, which uses load modulation. The DoA is estimated by array antenna at reader side, where multipath components are eliminated by using modulation codes. The experiments were conducted at 2.4 GHz band, and showed the direction...
This paper proposes a self-interference reduction method exploiting antenna arrangement and beamforming for space division duplex (SDD) relay station. When transmitting (Tx) and receiving (Rx) linear array antennas are placed in end-fire arrangement, spatial correlation between Tx and Rx increases. This causes rank degeneracy of the channel matrix between Tx and Rx. With this channel, almost all the...
In this paper, the frequency sharing technique between existing TV and new wireless communication systems are discussed. By adding a load modulation function to TV receiver antenna, the secondary system, i.e. new wireless communication system, can identify the interference channel between secondary system and primary TV receiver. The simulation has been carried out and it is found that the fairly...
In this paper, we show the method to reduce complexity of demodulation in passive Multiple-Input Multiple-Output (MIMO) scheme, which has been proposed to improve transmission rate in passive Radio Frequency Identification (RFID). In order to reduce complexity of Maximum Likelihood Detection (MLD), analog signal processing is used to decouple the streams by using beam-forming at receiver. On the basis...
A Multiple-Input-Multiple-Output (MIMO) channel manipulation using tunable passive repeater is presented in this paper. The passive repeater has multiple antennas and each of them has a phase-shifter function. The MIMO channel capacity is maximized by controlling all elements individually in the passive repeater. The effectiveness of the proposed passive repeater is evaluated numerically and experimentally...
This paper proposes miniaturized 6-element MIMO (Multiple-Input Multiple-Output) antenna using T-shaped inverted-F antenna and reactance-loaded notch antenna. Combination of T-shaped inverted-F antenna and reactively loaded notch antenna offers both miniaturization and orthogonalization of antenna elements. The numerical analysis results show the miniaturization of the antenna elements does not significantly...
Since the evaluation of multiple-input multiple-output (MIMO) antennas requires full information of its complex radiation patterns as well as propagation channels, its design procedures and analyses are cumbersome and complicated in general. In this letter, the accuracy of a closed-form capacity formula for mean MIMO channel capacity is investigated, where the -parameter of the antenna is needed...
In this study, we experimentally assessed the impact of tag element spacing on Bit-Error-Rate (BER) performance of passive Multiple-Input Multiple-Output (MIMO), which uses multiple antennas at both Radio Frequency Identification (RFID) tag and its reader to improve data-rate of the backscattering load modulation. Since a small RFID tag needs miniaturized multiple antennas, the antenna element spacing...
In this paper, a novel matching method for near field MIMO is proposed. A concept of image impedance matching is extended to 2×2 MIMO. A proposed matching network was fabricated and tested. The measurement results indicated the proposed matching network offers a high channel capacity since it significantly improves SNR in near field MIMO scheme.
The authors have proposed a direction estimation method of the living-body using array antenna in multi-path environment. However, this method has a problem that takes time as several tens of seconds. In this paper, we present a fast algorithm for estimating living-body direction. The experiment showed that the proposed method works well in estimating living-body direction with high accuracy in multi-path...
In this paper, miniaturized 6-element MIMO (Multiple-Input Multiple-Output) antenna using T-shaped inverted-F antenna and reactance-loaded notch antenna is experimentally evaluated. Combination of T-shaped inverted-F antenna and reactively loaded notch antenna offers both miniaturization and orthogonalization of antenna elements. The experimental results showed good matching and low mutual coupling...
This paper presents a localization method of multiple living-bodies suitable for multi-path environments. The time-variant Multiple-Input Multiple-Output (MIMO) channel is measured and the bistatic MIMO radar estimates multiple target locations from Fourier-transformed channel information. Measurements are carried out in an indoor environment, and it is shown the proposed method can estimate multiple...
Radar for estimating living-body direction has been studied, recently. However, the calibration of the array antenna is required since the phase error in the array antenna causes angle error in the estimated direction. In this paper, a simple calibration method that uses the channel response with known subject direction is presented. The experiment showed that the proposed method can calibrate the...
In this paper, the data-rate evaluation results of passive multiple-input multiple-output (MIMO) transmission are presented. In the passive MIMO technique, the load modulation is used at the tag and multiple antennas enhances the data-rate without extending the frequency band. From the experimental result, it is shown that the proposed passive MIMO scheme actually achieves 1.6 Mbits/s by using 2×2...
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