Doppler shift of radio-frequency signals in the ionospheric waveguide channel

1981 ◽  
Vol 24 (8) ◽  
pp. 635-638
Author(s):  
I. P. Stakhanov
Keyword(s):  
Radio Frequency ◽  
Doppler Shift ◽  
Waveguide Channel ◽  
Ionospheric Waveguide ◽  
Radio Frequency Signals

Coherent Passive Backscatter Communications Using Ambient Transmitters

2014 ◽  
Vol 5 (2) ◽  
pp. 23-43
Author(s):  
William C. Barott ◽  
Kevin M. Scott
Keyword(s):  
Radio Frequency ◽  
Low Complexity ◽  
Data Rate ◽  
Experimental Results ◽  
Digital Television ◽  
Passive Radar ◽  
Detection Range ◽  
Backscatter Modulation ◽  
Radio Frequency Signals ◽  
Processing Algorithms

A communications method is presented based on the backscatter modulation of incident radio frequency signals using low-complexity tags. The incident signals arise from digital television stations used as illuminators of opportunity. A receiver detects the tag using coherent processing algorithms similar to those used in passive radar, extending the detection range over published noncoherent techniques. This method enables shared use of the UHF television band for low-data-rate applications. While analyses suggest that rates exceeding 1 kbps might be achievable at 1 km range, experimental results demonstrate the challenges in designing and implementing such a system.

The Design of Passive RFID Reader System Based on MF RC500

2014 ◽  
Vol 1022 ◽  
pp. 135-138
Author(s):  
Song Lin Huang ◽  
Jian Zhong Cui
Keyword(s):  
Radio Frequency ◽  
Automatic Identification ◽  
Human Intervention ◽  
The Third ◽  
Rfid Reader ◽  
Radio Frequency Signals ◽  
Passive Rfid ◽  
Transfer Of Information ◽  
Electronic Tags ◽  
Reader System

RFID is a technology that uses radio frequency signals coupled to the space (alternating magnetic or electromagnetic), to achieve the purpose of non-contact transfer of information and automatic identification. In this paper, RFID reader system is designed based on the MF RC500. Compared with the automatic identification technology such as the barcodes, magnetic cards and IC cards, The RFID reader has many outstanding advantages: firstly, it is safe and suitable for high security terminal. The second, a plurality of electronic tags can be recognized simultaneously. The third, there is no mechanical wear. The fourth, it is convenient to use with non-contact operation and without human intervention when identifying.

Realization of Low Frequency Wakeup in Tire Encoded Radio Frequency Identification System

2014 ◽  
Vol 556-562 ◽  
pp. 2895-2898
Author(s):  
Wei Dong Yang ◽  
Li Li ◽  
Kai Peng
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Low Frequency ◽  
Vital Role ◽  
Simulation Software ◽  
Physical Models ◽  
Identification System ◽  
Radio Frequency Signals ◽  
Frequency Identification ◽  
Transmitted Waveform

In car tires coded identification system, radio frequency technology plays a vital role, the key to radio frequency signals transmitted process is waveform modulation. The key of adjusting the waveform is how to match its resistor and capacitor easily. In the paper their resistance and capacitance values are optimized by using the simulation software (Protues) to simulate the transmitted waveform, and based on matching results the optimized physical models are produced. The actual test results agree well with the simulation results. The method of simulation tests can save the resources effectively, and shorten the development time.

scholarly journals A Comparison of RFID Anti-Collision Protocols for Tag Identification

2018 ◽  
Vol 8 (8) ◽  
pp. 1282 ◽  
Author(s):  
Nikola Cmiljanic ◽  
Hugo Landaluce ◽  
Asier Perallos
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Communication Channel ◽  
Tag Identification ◽  
Collision Problem ◽  
Key Technologies ◽  
Different Types ◽  
Radio Frequency Signals ◽  
Frequency Identification ◽  
The Internet Of Things

Radio Frequency Identification (RFID) is a technology that uses radio frequency signals to identify objects. RFID is one of the key technologies used by the Internet of Things (IoT). This technology enables communication between the main devices used in RFID, the reader and the tags. The tags share a communication channel. Therefore, if several tags attempt to send information at the same time, the reader will be unable to distinguish these signals. This is called the tag collision problem. This results in an increased time necessary for system identification and energy consumption. To minimize tag collisions, RFID readers must use an anti-collision protocol. Different types of anti-collision protocols have been proposed in the literature in order to solve this problem. This paper provides an update including some of the most relevant anti-collision protocols.

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