A new directional coupler for UHF RFID reader

Abstract

ABSTRACT:

A novel design of organic semiconductor thin film device embedded microstrip antenna

“…Investigations on the near field output distribution (NFOPD) of such optical fibers have shown to be very useful in the areas implementing such fibers [3]. Using the wave propagation analysis the near field output power distribution of optical fibers can be formulated [4]. However, high dependency of the propagated modal fields up on the fiber environment and its lunching condition demands experimental information in addition to the theoretical considerations [5].…”

“…Effective coupling of couple of lossy layers on the FR4 substrate with high loss tangent and low dielectric coefficients was assumed. Experimentally, the mode excitation of the proposed microstrip antenna is from the size and shapes of electrodes of the OSTF device and the grounded substrate [2–4]. As the simulation result was reasonable closer to the measured value in anechoic chamber, the most useful application is to estimate the electron mobility in PN junction which is a severe concern in the advance study of OSTF device [5, 6].…”

Circuit and system design for an 860–960 MHz RFID reader front‐ends with Tx leakage suppression in 0.18 − µm CMOS technology

“…Assuming that the total disturbing power is divided equally (50 per cent 3 dB) between noise and distortion SNR = SIR= SNIR+3 dB. Thus, the NF is calculated for listen mode sensitivity of −90 dBm and SNR of 14 dB according to (1) and is summarized in Table I. In order to convert a single-ended signal from an antenna into a differential signal, a balun is usually placed before the LNA in direct conversion receivers.…”

“…Common outside receiver techniques are using separate antennas for RX path and TX path which results in a bulky system, using a directional coupler which is a compact and good‐isolation solution with a disadvantage of significant path loss or using a circulator which has a limited isolation performance. A commercial circulator, directional coupler or hybrid coupler generally provides about 25 dB of isolation characteristic in the well‐matched condition 1–5. Assuming 30 dBm for transmitter output power, the maximum transmitter carrier leakage in the receiver input is calculated as 10 or 5 dBm.…”

Wideband adaptive isolator for UHF RFID reader

“…In the case of the UHF RFID, the problem has been addressed in [4,5] by directional coupler design, providing good isolation at a narrow band. But as static devices, these cannot adapt to any change in coupling.…”