Phase Difierence Research Articles

Power Feeding to RFID Tags Within Specific Distance and Transponder Control Signal

We are proposing the method of supplying driving power of the RFID tag contain- ing transponder control signal by the electro-magnetic fleld besides the communication signal. From this viewpoint, we are also proposing power supplying method to RF tags within speciflc distance using two antennas. In the method, we use two properties: (1) The intensity of the electromagnetic fleld from two loop antennas sharply decreases depending on the distance, and (2) the supplied-signal phase difierence sharply changes at a position 1=(2…) of the wavelength. We used transmitting resonance-type antennas composed of capacitor of 1pF and the flve turns coil of 30cm in diameter, and receiving antennas composed of variable capacitor from 10pF to 120pF and the card-type coil with flve turns. The amplitude is 10V at the transmitting side, and the resonance-frequency is about 17.6MHz. Under this condition, we were able to drive an IC-encoder-chip of 2V and 0.3mA within the distance up to 70cm. Next, we proposed the ball-type antenna to induce only magnetic flelds mainly.

Improved Methods of Signal Processing Used in Low-Coherent Systems

In this article the author presents improved techniques of signal pro-cessing used in low-coherent measurement systems. The author proposesto utilize the synthesized sources in the system with the temporal signalprocessing. It will be shown that the exploit of such a source can substan-tially reduce the signal-to-noise ratio required to identify the central fringeposition. In case of using spectral signal processing, the author proposesto control the position of maximum in the spectral pattern which modiflesthe phase difierence between interfering beams. The results of experimentalworks will show that described techniques can be an efiective method forimproving the signal processing in low-coherent measurement systems.PACS numbers: 42.79.{e, 42.81.Pa