Application of Space-Time Signal Processing and Active Control Algorithms for the Suppression of Electromagnetic Fields

2011 ◽  
pp. 45-60
Author(s):  
Tommy Hult ◽  
Abbas Mohammed
Keyword(s):  
Active Control ◽  
Mobile Phones ◽  
Processing System ◽  
Antenna System ◽  
Space Time ◽  
Control Algorithms ◽  
Time Signal ◽  
Suggested Approach ◽  
Mimo Antenna ◽  
Effects Of Radiation

Several studies have been conducted on the effects of radiation on the human body. This has been especially important in the case of radiation from hand held mobile phones. The amount of radiation emitted from most mobile phones is very small, but given the close proximity of the phone to the head it might be possible for the radiation to cause harm. The suggested approach involves the use of adaptive active control algorithms and a full space-time processing system setup (i.e. multiple antennas at both the transmitter and receiver side or MIMO), with the objective of reducing the possibly harmful electromagnetic radiation emitted by hand held mobile phones. Simulation results show the possibility of using the adaptive control algorithms and MIMO antenna system to attenuate the electromagnetic field power density.

scholarly journals Space-time signal processing in MIMO antennas system with the Earth surface reflections

2019 ◽  
Vol 30 ◽  
pp. 15013
Author(s):  
Igor Krychkov ◽  
Gennady Slukin ◽  
Valery Chapursky
Keyword(s):  
Signal Processing ◽  
Elevation Angle ◽  
Antenna System ◽  
Space Time ◽  
Target Range ◽  
Time Signal ◽  
Surface Reflection ◽  
Correlation Integral ◽  
Mimo Antenna ◽  
Generalized Correlation

The generalized correlation integral for space-time signal processing at the output of a MIMO antenna system radio altimeter in the Earth’s surface reflections presence is obtained. The results of calculation of one-dimensional cross-section of the generalized correlation integral at an elevation angle with a known target range and two-dimensional crosssection of the generalized correlation integral «horizontal range-height» for specific surface reflection coefficient are presented.

scholarly journals Dual MIMO Antenna System for 5G Mobile Phones, 5.2 GHz WLAN, 5.5 GHz WiMAX and 5.8/6 GHz WiFi Applications

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Phalguni Mathur ◽  
Robin Augustine ◽  
M. Gopikrishna ◽  
Sujith Raman
Keyword(s):  
Mobile Phones ◽  
Antenna System ◽  
Mimo Antenna

scholarly journals Power Constrained Space-Time Processing for Suppression of Electromagnetic Fields

2017 ◽  
Vol 1 (1) ◽  
pp. 71 ◽  
Author(s):  
Tommy Hult ◽  
Abbas Mohammed
Keyword(s):  
Electromagnetic Field ◽  
Power Density ◽  
Active Control ◽  
Mimo System ◽  
Superposition Principle ◽  
Human Head ◽  
Antenna System ◽  
Space Time ◽  
Time Processing ◽  
Transmitting Antenna

Active suppression of noise and vibrations is a well established field of research with many applications in acoustic and mechanical industries. In this paper we investigate the possibility of applying these adaptive active control methods with the aim of lowering the electromagnetic power density at a specific volume in space using the superposition principle and space-time processing employing the full MIMO (Multiple Input Multiple Output) antenna system setup. The application that we evaluated is a model of a mobile phone equipped with one ordinary transmitting antenna and two actuator-antennas whichpurpose is to cancel out the electromagnetic field at the human head while maintaining a predefined level of the overall output power of the system. This power control is achieved through the use of a quadratic constraint on the active control algorithm. Simulation results show the promise of using the adaptive control algorithms and MIMO system to attenuate the electromagnetic field power density.

scholarly journals FOUR-ELEMENT DUAL-BAND MIMO ANTENNA SYSTEM FOR MOBILE PHONES

2015 ◽  
Vol 60 ◽  
pp. 47-56 ◽  
Author(s):  
Lingsheng Yang ◽  
Hongling Xu ◽  
Jianping Fang ◽  
Tao Li
Keyword(s):  
Mobile Phones ◽  
Antenna System ◽  
Dual Band ◽  
Mimo Antenna

Active control of compressor noise in the machinery room of refrigerators

2019 ◽  
Vol 67 (5) ◽  
pp. 350-362
Author(s):  
J. M. Ku ◽  
W. B. Jeong ◽  
C. Hong
Keyword(s):  
Control System ◽  
Active Control ◽  
Weighting Function ◽  
Reference Signal ◽  
Active Noise Control ◽  
Dominant Frequency ◽  
Time Signal ◽  
Frequency Noise ◽  
Sound Power ◽  
Fxlms Algorithm

The low-frequency noise generated by the vibration of the compressor in the machinery room of refrigerators is considered as annoying sound. Active noise control is used to reduce this noise without any change in the design of the compressor in the machinery room. In configuring the control system, various signals are measured and analyzed to select the reference signal that best represents the compressor noise. As the space inside the machinery room is small, the size of a speaker is limited, and the magnitude of the controller transfer function is designed to be small at low frequencies, the controller uses FIR filter structure converged by the FxLMS algorithm using the pre-measured time signal. To manage the convergence speed for each frequency, the frequency-weighting function is applied to FxLMS algorithm. A series of measurements are performed to design the controller and to evaluate the control performance. After the control, the sound power transmitted by the refrigerator is reduced by 9 dB at the first dominant frequency (408 Hz in this case) and 3 dB at the second dominant frequency (459 Hz here), and the overall sound power decreases by 2.6 dB. Through this study, an active control system for the noise generated by refrigerator compressors is established.

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