Definition, Characteristics and Determining Parameters of Antennas in Terms of Synthesizing the Interrogation Zone in RFID Systems

The radio frequency identification (RFID) systems are gaining in popularity in automated processes of object identification in various socioeconomic areas. However, despite the existing belief, there is no universal RFID system on the commercial market that could be used in all user applications. All components of a developed solution should be carefully selected or designed according to the specification of objects being recognized and characteristics of their environment. In order to determine parameters of propagation or inductively coupled system, especially when it is dedicated to uncommon applications, a multiaspect analysis has to be taken into consideration. Due to complexity, the problem is reduced to analytical or experimental determination of RFID system operation range and a “trial and error” method is mostly used in the industry practice. In order to cope with the barriers existing in the RFID technology, the authors give the review of latest achievements in this field. They focus on the definition, comprehensive characteristics and determination of the antenna parameters. They also pay attention to the 3D interrogation zone (IZ) that is the main parameter in which multitude technical aspects of the RFID systems are gathered simultaneously, as regards the theoretical synthesis as well as market needs

Numerical Model of Directional Radiation Pattern Based on Primary Antenna Parameters

The new numerical model of directional radiation pattern, in which part of energy is emitted in side and back lobs, has been presented in this paper. The model input values are determined on the base of primary parameters that can be read from the datasheet of used antennas. The special software tool NmAntPat has been elaborated to carry out the described task. The elaborated model, program and output files can be easily implemented into an analysis of radio wave propagation phenomenon in any algorithms and numerical calculations. The comparison of the graphical plots that have been obtained on the base of measurements, producers’ data specification notes and modelling results confirms the model correctness

The idea of enhancing directional energy radiation by a phased antenna array in UHF RFID system

The interrogation zone IZ is the most important parameter when RFID systems are considered. Its predictability is determined by the construction and parameters of antenna built in a read/write device. The IZ should be of sufficient size and appropriate to requirements established for an application of object automated identification. The method of shaping an antenna radiation pattern provides effective yet unconventional opportunities in this area. The idea and practical solution of the phased antenna array dedicated to UHF read/write devices are presented in the paper. On the basis of tests carried out, the authors pointed out the possibility of using developed devices for the synthesis of a determined IZ in anti-collision RFID system

Determination of the material relative permittivity in the UHF band by using T and modified ring resonators

The complete methodology of designing T- and modified ring resonators in the UHF band are presented in the paper. On the basis of proposed algorithms, the dedicated software tool has been elaborated in order to determine material parameters of contemporary substrates. The program is implemented in the Mathcad environment and it includes the base of information on known materials used in electronic products. Also, test sample series for selected substrate materials (IS680, FR408, I-SPEED PCB ISOLA and A6-S LTCC FERRO) and operating frequencies from 1 GHz to 3 GHz are analyzed in details. The special test stand with a vector network analyzer has been applied in experiments. The obtained data of relative permittivity measurements and model calculations are described, discussed and concluded

Modelling and Design of HF RFID Passive Transponders with Additional Energy Harvester

The huge progress in electronics technology and RFID technique gives the opportunity to implement additional features in transponders. It should be noted that either passive or semipassive transponders are supplied with energy that is derived from the electromagnetic field generated by the read/write device and its antenna. This power source is used to conduct radio-communication process and excess energy could be used to power the extra electronic circuits, but the problem is to determine the additional power load impact on the RFID system proper operation and size of interrogation zone. The ability to power the supplementary electronic blocks applied in the HF passive transponders is discussed in detail this paper. The simulation model and test samples with a harvester that recovers energy from the electromagnetic field of read/write device and its antenna have been developed in order to conduct investigations. The harvested energy has been utilized to supply a microprocessor acquisition block for LTCC pressure sensor developed in research previously described by authors

Evaluation of the oral cavity state and Candida occurence in generally healthy Polish and foreign dental students

Aim of the study. This study aimed at comparing the oral cavity condition and Candida prevalence in generally healthy Polish and foreign dentistry students and evaluating the relationship between Candida occurrence and the oral cavity condition. Material and methods. 79 dentistry students with no systemic diseases, aged 20–25 (mean 23.5), were examined in the present study. Two groups of examined subjects were specified: 43 Polish students (group I) and 36 foreign students (group II). Group II has been divided into subgroups: IIa – students from Taiwan and IIb – students from Europe and USA. Occurence of oral mucosa lesions, periodontal treatment needs (CPITN), caries prevalence (DMFT) and oral hygiene (OHIs) were investigated. Evaluation of Candida occurrence on the oral mucosa was included in the study. Results. Comparison of the oral cavity condition in Polish and foreign students showed no significant difference, with the exception of the number of teeth with active caries, that was significantly higher in foreign students (D 1,2) than in Polish students (D 0.4). Mean indices rates in the group I were: CPITN 0.9; PUWz 8.7; OHI-s 0.4 in the group II 1.0; 7.0; 0,5, respectively. The most commonly observed oral mucosa lesions, in both groups, were white coated tongue and buccal white line. Candida was found in 38,0% of the subjects, its prevalence was similar in both groups (I – 34.9%, II – 41.7%). No correlation between Candida occurence and oral cavity state was detected. Higher frequency of active caries in Candida carriers was the exception

Symptomatic vertebral hemangioma related to pregnancy. A case report

Hemangioma is the most common primary tumor of the spine. Pregnancy is a risk factor increasing the possibility of disclosure or exacerbation of symptoms of spinal hemangioma. This paper presents a case of 32-year-old woman with hemangioma of Th6 vertebrae, which was revealed by paresis of the lower limbs and sphincters dysfunction at 34 weeks gestation. Pregnancy has ended with a cesarean section. Then posterolateral thoracotomy and removal of hemangioma were performed. Spinal cord was decompressed and stabilization of the spine with metal implants was carried out. Histological examination discovered cavernous hemangioma weaving. The patient is followed up in the outpatient clinic. Despite the improvement of neurological status – enhancement of the sensory function and development of bladder and rectal sphincter automatism – she did not regain the ability to walk alone

Managed care after acute myocardial infarction (MC-AMI) reduces total mortality in 12-month follow-up : results from a Polands national health fund program of comprehensive post-MI care - a population-wide analysis

Introduction: Advances in the acute treatment of myocardial infarction (AMI) substantially reduced in-hospital mortality, but the post-discharge prognosis is still unacceptable. The Managed Care in Acute Myocardial Infarction (MC-AMI) is a program of Poland’s National Health Fund that aims at comprehensive post-AMI care to improve long-term prognosis. The aim of the study was to assess the effect of MC-AMI on all-cause mortality in one-year follow-up. Methods: MC-AMI includes acute MI treatment, complex revascularization, cardiac rehabilitation (CR), scheduled one-year outpatient follow-up, and prevention of sudden cardiac death. In this retrospective observational study performed in a province of Silesia, Poland, we analyzed 3893 MC-AMI participants, and compared them to 6946 patients in the control group. After propensity score matching, we compared two groups of 3551 subjects each. To assess the effect of MC-AMI and other variables on mortality, we preformed a Cox regression. Results: MC-AMI was related with mortality reduction by 38% in a 12-month observation period and the effect persisted even after. Multivariable Cox regression analysis revealed MC-AMI participation to be inversely associated with 1-year mortality (HR 0.52, 95%CI 0.42–0.65, p < 0.001). Besides that, older age (HR 1.47/10 y), ST-elevation AMI (HR 1.41), heart failure (HR 2.08), diabetes (HR 1.52), and dialysis (HR 2.38) were significantly associated with the primary endpoint. Among MC-AMI components, cardiac rehabilitation (HR 0.34) and strict outpatient care (HR 0.42) are the crucial factors affecting mortality reduction. Conclusions: Participation in MC-AMI reduced 1-year mortality by 38% and the effect persisted after the program had been completed