Essay: RFID Technology And Reconfigurable Antennas: A Review.

Study the articles on these topics given below and write your review critically summarizing and commenting on the research published in these articles.

List the topic of your review:

. MEMS-based antennas
. Reconfigurable Antennas for Body Area Networks
. Circular-Polarization reconfigurable antennas
. Reconfigurable RFID antennas and applications
. Leaky-wave Antennas
. Substrate-Integrated Waveguide Technology

Varacter-loaded active compact antenna

Wireless communication has been enhanced by growing rapidly in the market in recent years. The collaboration of RFID with various technology has been including computer technique, integrated circuit technique and communication technique. There has been a working range of Radio Frequency Identification (RFID) technology that covers 13.6 MHz in high band range 100-500 KHz in the low band range and microwave band range including 860-960 MHz and 2.45 GHz. RFID technology has been developing by using Radio Frequency (RF) signals for automation in identifying objects. In RFID systems, performance has been the maximum read range by which RFID reader can be detected. Therefore, the read range has been sensitive in order to tag orientation on which tag has been placed. The antenna helps in determining performance of tag stuck into a object. The antenna has been determining performance of tag stuck in the object. The tag antenna needs to be small in size and low in profile. The range of frequency from 120-150 KHz is used for factory data collection and animal detection, the range of frequency in 13.56 MHz is compatible with smart cards and ISO compatible memory cards. The ultra high frequency of 433 MHz is applied in defense that has active tags in it. The microwave range is used in WLAN and in Bluetooth standards. The frequencies in Giga Hertz range requires either active or semi-active tags. A Radio Frequency Identification tag has been an antenna compromise with microchip in a package.

1. RFID System Overview with Theoretical Consideration
2. Antenna equations

The communication in various microwave RFID and passive UHF systems has been based on backscattering. RFID tag include an antenna and microchip that helps in sending information back to reader and switches between two states. Signals that RFID reader antenna receives has been forwarded and reversed by different communication. RFID has been using simple modulations including amplitude-shift keying frequency shift keying and phase shift keying.

Figure 1: Generic backscattered RFID system.

(Source: Nikitin, 2017)

The power density at distance R1 from the transmitting antenna in the direction (θ trans , φ trans) is:

W_trans= {P_transG_trans(θ_trans,φ_trans)}/4πR2

where P_trans is the input power of transmitting antenna and G_trans is the gain of transmitting reader antenna. P_transG_trans is called reader-transmitted equivalent isotropic radiated power (EIRP). The power received by the RFID tag antenna is expressed by the following antenna formula:

Ptag=W_transG_tag(θ_tag, φ_tag) λ₂ /4π |ρ _trans.ρ _tag| ²

The surface waves has been flowing on antenna can be excited by travelling across dielectric substrate. However, these waves have reached to edges of substrate as reflected, diffracted and scattered. This also help in increasing cross-coupling between array elements. This excitation of surface waves has been a function of ε_r and h. The loss in power of surface waves has been increased with increase in thickness, h/ λ₀ of the substrate. The loss can be neglected when h satisfies below criterion:

h /λ₀ ≤ 0.3 /2π √εr

The equivalent circuit of a rectangular microstrip antenna has been a parallel combination of resistance R, inductance L and capacitor C. According to modal expansion cavity model, the values of R, L and C are mentioned below:

Tag antenna structure

C = (ε₀εe_lω /2h) cos−2(πd/l)

L = 1 /ω2C

R = Qr /ωC

 Q_r = C√εr/ 4fh

Here, c is velocity of light, d is the feed-point location, ω = 2πfr, f r is the design frequency, Qr is the radiation quality factor, and ε_e is the effective permittivity of the medium. The varacter diode when reverse-biased.

This study has been simulated on an FR4 substrate having relative permittivity of 4.6, width of 1.6 mm and dimensions of 103*33mm². This antenna consists of loop for feeding and meandered dipole. There has been a proposed RFID diagram, given below:

Figure 2: Schematic of the proposed varactor-loaded antenna for RFID tag

(Source: Amendola et al. 2018)

The fractal dipole antenna has a rectangular compact shape and pair of meander patches with a metal length of 23 mm and a width of 1 mm.  There has been an end gap distance of 2 mm between meander patch end and microstrip line. The optimal dimensions of the proposed antenna are W1 = 33 mm, L1 = 41.5 mm, W2 = 3 mm, W3 = 2 mm, L2 = 9.3 mm, L3 = 23 mm, and L4 = 15.2 mm. The dimensions of the antenna were first studied with AWR Microwave Office simulation electromagnetic software and then verified by the experiment.

Figure 3: Radiation pattern comparisons of proposed antenna: a) radiation patterns of proposed antenna with all varactors OFF at 2.4 GHz, b) radiation patterns of proposed antenna with all varactors ON at 2.4 GHz

(Source: Ji et al. 2016)

The authority IEEE meaning of a radio wire as given by Stutzman Microstrip radio wires are notable for their highlights, for example, low profile, light weight, minimal effort, comparability to planar and non-planar surfaces, inflexible, and simple establishment. They are most normally fused into portable, specialized gadgets due to minimal effort and flexible structures. An accentuation has been given in microstrip radio wire and reconfigurable gap, with the end goal to accomplish different octave tunability. Reconfigurable multiband space radio wires are accepting a considerable measure of consideration of late because of the development of RF-MEMS switches (Chen & Wong 2018). Regularly microstrip radio wires are additionally alluded to as fix reception apparatuses (Ji et al. 2016). The element of self-comparability of a fractal recieving wire can likewise give a premise to the plan of various recurrence radio wires. These reception apparatuses have the preferred standpoint that they emanate comparable examples in an assortment of recurrence groups. The significant antecedent is the broadly examined Sierpinski gasket. The different fractals shape that gang self-likeness have been connected to multi-band or scaled down radio wire structure. There are numerous fractal geometries, for example, Sierpinski gasket, Sierpinski cover, Koch Island, Hilbert bend and Minskowsi and so on has been utilized in fractal radio wires.  Reconfigurable antenna has been demonstrated in various research papers in the way to switching from single band to narrow band. The range of frequency from 120-150 KHz is used for factory data collection and animal detection, the range of frequency in 13.56 MHz is compatible with smart cards and ISO compatible memory cards. The ultra high frequency of 433 MHz is applied in defense that has active tags in it. The microwave range is used in WLAN and in Bluetooth standards. These antennas have been helping in switching the ireless signals into proper wavelength for clear and concise communication.  These antennas have been helping in enhancing the several telecommunication fields in the market.  The use of antenna has been creating a revolution in the telecommunication system. The RFID antennas have been designed with multiband antenna for RFID applications for applicable for several standards.

RFID technology and reconfigurable antennas

A few strategies were drawn closer in structure the multifrequency from a solitary radio wire (Narbudowicz, Ammann & Heberling 2016). To track the tags attached to objects radio frequency identification use electromagnetic fields. The majority of RFID receiving wires were intended to work at least one recurrence groups, Low Frequency, Ultra High Frequency, High Frequency and Microwave. Every one of recurrence groups has their own favorable circumstances. Accordingly, the desire of multiband RFID reception apparatuses is getting to be distinctive. RFID find application in various sectors including automobile industry. Therefore, there are numerous papers were structured a multiband recieving wire for RFID applications which was pertinent for a few guidelines. Because of various overall controls, the recurrence groups have unique areas in the range.  

Second dipole arm has been associated with ground. For this proposed receiving wire, ground plane are not required. The last measurements of improved dipole stacked with Cshaped fix structure is appeared on Table I. The tags can be either active or passive. Encoded radio signal is transmitted through RFID reader. The message is received by the tag and then responds to the identification as well as other information. A passive tag is cheaper than active as it does not use any battery. The type of reader and tag classifies RFID systems. There are two types of tag like active reader active tag and active reader passive tag. The improvement is finished by two sections. For a solitary band, hypothesis of dipole receiving wire is connected by differing the parameters of L1, W1, L2 also, W2. For the double band frequencies, the C-molded fix structure is broke down for parameters a, b, c and d as clarified partially c. The space measurement (a mm × b mm) is caused the recurrence of full and data transfer capacity for upper band. The examination is done inside the scope of 5 mm ≤ a ≤ 13 mm and 13mm ≤ b ≤ 19 mm. The lower band is performed relies upon length of dipole and extent of rectangular fix (c mm × d mm). The scope of length, c is broke down from 19 mm to 27 mm and for the length of d, from 18 mm to 22 mm.

RFID with passive tags use induced antenna for voltage operation. The AC voltage that is supplied to the RFID antenna is rectified by full wave rectifiers to provide DC voltage. The wavelength of frequency having value of 13.56 MHz is 22.12 meters. As a result a true antenna cannot be formed for RFID antennas. The proposed radio wire is planned on a Fire Retardant-4 board (FR4) with the measurement of 90 × 25 mm2 in size which has a relative dielectric steady of εr = 4.7 with digression loss of 0.019 and it has a 1.6 mm substrate thickness furthermore, a 0.035 mm copper thickness (Fu & Yang, 2015). A planar dipole recieving wire is structured as essential receiving wire reverberating as lower band with omni-directional radiation design.

Conclusion

The proposed rectangular fix (c × d) as a transmitting component is intended to be stacked with dipole radio wire in supporting solid flows and radiation at reverberation. As appeared in Fig. 1, structure of C-molded fix is portrayed where an is space width, b is the opening length, c is the length of the rectangular fix and d is the length of the rectangular fix. The consolidated structure of C-formed patches radio wire what's more, the dipole radio wire at both length components is observed to be resounding at double band. The examination of the arrival misfortune bends when a is shifted is appeared in Fig. 3. The rectangular fix 19 × 22 mm2 is stacked with dipole radio wire (when a = 0), just a solitary reverberation recurrence is performed at 1 GHz. In this manner, as the estimation of an is shifted in the range, 5 mm ≤ a ≤ 13 mm, the scope of lower recurrence is diminished from 0.951 GHz to 0.885 GHz and the scope of upper recurrence is expanded from 2.367 GHz to 2.499 GHz. Besides the investigation of space length is finished by fluctuated by the scope of 13mm ≤ b ≤ 19 mm as residual the estimation of a = 9 mm, c = 19 mm and d = 22 mm. By changing the measurement of significant worth b, the bandwith for upper band are affected and the bandwith of lower band is stay consistent (Ullah et al., 2018). At point when the opening length is decreased, the execution of data transmission and recurrence resounding are changed. However, data transmission of lower recurrence very little changes, nearly 80 MHz when the estimation of b is expanded by 13 mm, 15 mm, 17 mm and 19 mm. Then again, the thunderous recurrence of upper band is raised to higher recurrence as the estimation of b is diminished. The induced voltage in an antenna is governed by Faraday’s law. . The range of frequency from 120-150 KHz is used for factory data collection and animal detection, the range of frequency in 13.56 MHz is compatible with smart cards and ISO compatible memory cards. The ultra high frequency of 433 MHz is applied in defense that has active tags in it. The microwave range is used in WLAN and in Bluetooth standards. The diameter of reader coil, the B-field, the number of turns and the DC resistance can be calculated. The inductance of the various coils used in the antenna should be calculated. All the calculation is done following certain formula.  Accordingly, the length space measurement is caused the recurrence of thunderous and bandwidth for upper band is changed. As appeared in Fig. 4, the upper recurrence can be balanced at the point when estimation of d is differed between the range 18 mm ≤ d ≤ 22 mm by residual the estimation of a = 9 mm, b = 19 mm and c = 19 mm to play out a required upper recurrence. In any case, the length of dipole arms must be stayed as 44.5 mm. As the estimation of d expanding, the lower recurrence resounding is somewhat diminished from 0.921 GHz to 0.885 GHz with the little contrasts of changes that are around 3%. At long last, the investigation of c estimation of C-formed patches which is caused the resounding recurrence of lower band affected. The width of rectangular fix is changed between the range, 19 mm ≤ c ≤ 27 mm. There has been a working range of Radio Frequency Identification (RFID) technology that covers 13.6 MHz in high band range 100-500 KHz in the low band range and microwave band range including 860-960 MHz and 2.45 GHz. RFID technology has been developing by using Radio Frequency (RF) signals for automation in identifying objects. Subsequently, the lower recurrence is diminished from 0.89 GHz to 0.81 GHz as the estimation of c is expanded inside the range. The level of the distinctions of lower recurrence is relatively 2.3 % when the c is balanced with 19 mm, 21 mm, 23 mm, 25 mm and 27 mm (Rezvani & Zehforoosh, 2017). In any case the level of contrasts for upper recurrence is little, 0.3 % where recurrence run is from 2.466 GHz to 2.493 GHz. In working as a reconfigurable multiband recieving wire, the switch is put in the middle of dipole arm and the C-molded fix recieving wire for the two components (ElMahgoub, 2016). To work MEMs switch legitimately, the source what's more, deplete of the switch ought to keep up voltage 0 V. The coordinate incorporation of dc predisposition line is intended to incite the switch and the fix radio wire is associated with dc ground plane to have the dc coherence. At the point when the turn is OFF at voltage 0 V, a dipole reception apparatus is worked as a solitary band. At the point when the switch is ON, the immediate current way is made over the hole between the two patches which is reverberating a lower and upper recurrence.

Conclusion

A minimized dipole reception apparatus was created and could accomplish a wide data transfer capacity and viable radiation design over the whole working band. From the examination of the RFID label reception apparatuses, it has been discovered that the feed structure, conservativeness strongly affected the reception apparatus' working data transmission and radiation design. There has been a working range of Radio Frequency Identification (RFID) technology that covers 13.6 MHz in high band range 100-500 KHz in the low band range and microwave band range including 860-960 MHz and 2.45 GHz. RFID technology has been developing by using Radio Frequency (RF) signals for automation in identifying objects. Reproduction and estimation results demonstrated it by picking a fractal shape and a metal wander fix, tuning their measurements, working transmission capacity was 12% and stable radiation examples could be gotten. The label reception apparatus reaction was estimated as – 65.56 dB at the 2.42 GHz ISM band while the reference recieving wire reaction was estimated as – 68.07 dB at 2.46 GHz. Moreover, a novel recurrence technique for minimal dipole reception apparatuses was proposed and approved through reasonable estimations.

References

Nikitin, P. (2017, May). Self-reconfigurable RFID reader antenna. In RFID (RFID), 2017 IEEE International Conference on (pp. 88-95). IEEE.

Amendola, S., Occhiuzzi, C., Manzari, S., & Marrocco, G. (2018). RFID-based multi-level sensing network for industrial internet of things. In New advances in the internet of things(pp. 1-24). Springer, Cham.

Chen, Z., & Wong, H. (2018). Liquid dielectric resonator antenna with circular polarization reconfigurability. IEEE Transactions on Antennas and Propagation, 66(1), 444-449.

Ji, L. Y., Qin, P. Y., Guo, Y. J., Ding, C., Fu, G., & Gong, S. X. (2016). A wideband polarization reconfigurable antenna with partially reflective surface. IEEE Trans. Antennas Propag, 64(10), 4534-4538.

Narbudowicz, A., Ammann, M. J., & Heberling, D. (2016). Reconfigurable Axial Ratio in Compact GNSS Antennas. IEEE Transactions on Antennas and Propagation, 64(10), 4530-4533.

Ahmad, A., Arshad, F., Naqvi, S. I., Amin, Y., Tenhunen, H., & Loo, J. (2018). Flexible and Compact Spiral-Shaped Frequency Reconfigurable Antenna for Wireless Applications. IETE Journal of Research, 1-8.

Fu, Z., & Yang, F. (2015). A slotted patch antenna integrated with thermal switch for high-sensitivity temperature monitoring. IEEE Antennas and Wireless Propagation Letters, 14, 998-1001.

Ullah, S., Ahmad, S., Khan, B. A., Ali, U., Tahir, F. A., & Bashir, S. (2018). Design and Analysis of a Hexa-Band Frequency Reconfigurable Monopole Antenna. IETE Journal of Research, 64(1), 59-66.

ElMahgoub, K. (2016). Slotted triangular monopole antenna for UHF RFID readers. Applied Computational Electromagnetics Society Journal, 1(1), 24-27.

Rezvani, M., & Zehforoosh, Y. (2017). Design of Multi-band Microstrip Antenna for Wireless Communications and ITU Applications. National Academy Science Letters, 40(5), 331-334.