Adaptive Noise-Resistant Low-Power ASK Demodulator Design in UHF RFID Chips

This paper presents a new signal demodulator for ultra-high frequency (UHF) radio frequency identification (RFID) tag chips. The demodulator is used to demodulate amplitude shift keying (ASK) modulated signals with the advantages of high noise immunity, large input range and low power consumption. The demodulator consists of a charge pump, an envelope detector, and a comparator. In particular, the demodulator provides a hysteresis input signal to the comparator through two envelope detectors, resulting in better noise immunity. The demodulator is based on a standard 0.13 µm CMOS process. The demodulator is suitable for demodulating high frequency signals at 900 MHz with a data rate of 128 Kbps and can operate up to 78 °C. The input signal has a peak of 1.2 V and consumes as little as 113.6 nW. The demodulator also has a noise immunity threshold of approximately 3.729 V.

Analysis of large-scale UHF-RFID use-cases utilizing full-wave simulation techniques

UHF-RFID is a mature and widespread technology that has the potential to increase the reliability and efficiency of processes in logistics and production environments. However, complex interference effects in indoor environments pose challenges to the implementation of reliable wireless communication systems like RFID. This work proposes a method for tag performance evaluation utilizing a coherent two-stage rating process. This enables the abstraction of physical quantities and facilitates the interpretation of tag readability. For this purpose, two well-established full-wave techniques are utilized to perform deterministic simulations of a logistical UHF-RFID use-case. The setup of large-scale simulation environments is discussed and important quantities to be considered in RFID-systems are derived. Based on the simulation results and the proposed rating method, the RFID use-case is evaluated. Results are visualized in full-3D, facilitating the identification of critical spots. Furthermore, a subsequent cross-validation of the simulation results is performed, verifying the validity of the simulation results. By performing a priori propagation analysis, issues can effectively be revealed beforehand and costly modifications after system deployment can be avoided.

The Effects of Refilling Additional Rooting Material on Exploration Duration and Tail Damages in Rearing and Fattening Pigs

Pigs housed in commercial barns with slatted floors cannot fully perform their natural behavioral needs such as rooting or exploring. Enrichment materials can stimulate these behaviors in pigs. Here, we investigated whether exploration can be stimulated by offering additional enrichment material, i.e., chopped straw, once compared to four times daily. In two replicates each with four rearing and eight fattening pens, a total of 192 pigs with undocked tails continuously received chopped straw from a dispenser, while a stimulus to explore was given by filling the rooting area of the dispenser either once (R1) or four times (R4) daily with additional chopped straw. The dispensers were equipped with an ultra-high-frequency radio-frequency-identification (UHF-RFID) system in order to record the exploration durations of each individual pig at the dispenser. At four times throughout rearing and fattening, pigs were weighted and tail injuries and length losses were assessed. This resulted in three temporal sections within each replicate, for each of which the difference in tail length to the previous section (Δ-tail length) was calculated. Exploration durations did not change in long-term but increased from rearing throughout fattening. The refillings in which additional chopped straw was offered (R1 vs. R4) did not affect the overall exploration duration during rearing (linear mixed effects model (LME), P = 0.85) or fattening (LME, P = 0.66). However, descriptive evaluations showed that exploration durations decreased within the first 10-min sequences within the hour after refilling the rooting area with additional chopped straw in both treatments (R1 and R4). Exploration durations were affected by week, day, and hour within day during rearing (LME, all factors, P < 0.0001) and fattening (LME, all factors, P < 0.0001). Neither tail injuries nor length losses were affected by the refilling treatment (R1 vs. R4) during rearing (GLMM, both P > 0.1) or fattening (GLMM, both P > 0.1). Offering additional straw four times compared to once a day had no advantage in the present setting with regard to exploration duration and tail damages of pigs. However, refilling the rooting area with additional chopped straw triggered a short-term increase of exploration that decreased within 1 h, thus, exploration was more spread over the day.