Pornanong Pongpaibool

An optimization study on multi-section dipole antenna designs for printed UHF RFID

In this paper, we present an optimization study on multi-section dipole antenna designs for printed UHF RFID, in which the antenna structure is divided into several unequal sections of radiating areas. The optimization work is extensively performed on the thickness, the length, as well as the width of each section in order to obtain optimal-performance multi-section printed dipole antennas at the lowest possible cost. The simulation results illustrate that a four-section dipole antenna structure with each succeeding section having the width approximately equal to half the width of its prior section achieves superior antenna efficiency performance. The conductive ink consumption of this antenna design is reduced around 51% when compared with the conventional flat layer design in order to achieve the same level of antenna efficiency performance as the ideal copper-trace dipole antenna.

Sensor Networks for Acoustic Source Localization Using Acoustic Fingerprint in Urban Environments and Construction Sites

We investigate the feasibility and performance of the acoustic localization system using the acoustic fingerprint for asynchronous wireless sensor network (WSN) in urban environments and construction sites. The location estimation is calculated by comparing the acoustic fingerprint obtained from multiple sensors with those pre-computed in the database. To calculate the fingerprint, we avoid expensive measurement process by using a 2-dimensional finitedifference time-domain (FDTD) to approximate acoustic propagation in urban area. The implementation cost for constructing the acoustic fingerprint map using FDTD is small compared to that of the exhaustive data measurements over an entire test site. We select the direction-of-arrival (DoA) of the first arrival path of the acoustic signal as a location fingerprint to avoid complexity from synchronization. The fingerprint from each node is weighted by the measured amplitude of the received acoustic waveform to take into account the decrease in the amplitude due to the distance between the source and the sensor node. We test our proposed localization algorithm at the 140x80 m artificial village area used for military drills. With proper node placement, our proposed algorithm can achieve strong localization performance using small number of sensor nodes. In particular, the root-mean-square-error (RMSE) between the estimated and accurate source position is 6.30 meters using observations from only 3 sensor nodes. Our proposed algorithm exhibits robustness to DoA estimation error representing the cumulative effect of uncertainties in urban environments and construction sites.

An optimized ink-reducing hollowed-out arm meander dipole antenna structure for printed RFID tags

This paper presents an optimized ink-reducing meander dipole antenna structure suitable for implementing printed radio frequency identification (RFID) tags. The proposed antenna designs contain empty ink-reducing hollowed-out areas along the antennas arms such that the resulting antennas require much less conductive ink to produce yet still achieve decent antenna performance compared with the conventional solid-arm dipole antennas. The simulation results demonstrate that when the ratio between the width of the hollowed-out areas and the width of the antenna arms is about 0.6, the resulting RFID tag experiences a slight read range performance degradation of

Multilayer Notch Loaded Antenna with Superstrate Layer of 90 deg Tilted Elements for Wireless Communications

A multilayer notch-loaded antenna for dual-band (L & S) operation has been proposed in this paper for wireless communications. The antenna is multilayered with dielectric layers of FR4 and Rogers/Duroid. A superstrate layer has been introduced with square shaped elements angled at 90 degrees to each other with an empty space just above the patch. The proposed structure of the antenna with superstrate layer is applicable to low frequency consecutive dual-band operations. The antenna also shows very good radiation characteristics with a gain of more than 7.0 dB and side lobe levels reduced to a very good extent of around −20 dB.

A cost-efficient printed Planar Inverted-F Antenna (PIFA) design via selective antenna area thickening/thinning for mobile devices

In this paper, we present a cost-efficient printed multi-zone printed Planar Inverted-F Antenna (PIFA) structure based on a selective antenna area dimensioning design approach. In the proposed design, the top plate and the ground plane of PIFA both contain some relatively small triangle-shape areas located near the feed point. These small feed areas are made significantly thicker than other antenna areas. The simulation results show that the proposed PIFA design can considerably reduce the amount of conductive ink required to produce the antenna by as much as 60%.

A study of multi-conductivity dipole antenna for printed UHF RFID

In this paper, we propose a multi-conductivity dipole antenna design for a printed UHF RFID, in which the printed conductive layer of the antenna has a flat layer thickness and comprises of multiple conductive areas fabricated by conductive ink with different conductivity. High-conductivity ink is printed near the feed areas and low-conductivity ink is used for other areas. The proposed antenna structure may be printed in just one printing cycle using an adapted multi-color ink cartridge in an inkjet printing system. Thus, the costly and time-consuming reprinting process is avoided. The simulation results illustrate that the proposed multi-conductivity dipole antenna can achieve higher antenna efficiency performance. The total cost of conductive materials required for the proposed dipole antenna design can also be lower when the conductivity and price characteristics are properly selected.

An annular microstrip antenna with sectoral slots for RFID reader

This paper presents an annular microstrip antenna with two sectoral slots fed by a coaxial probe on a square vertical ground plane. The proposed microstrip antenna can support the dual-band operation (UHF and microwave RFID bands). From the results, the antenna has the magnitude of S11 less than −10 dB along the bandwidth of 32 MHz (3.51%) for UHF band and 140 MHz (5.76%) for microwave band. The unidirectional beam can be achieved by the proposed microstrip antenna. The beamwidth in xz- and yz-planes is 82.8 and 89 degrees at the center frequency of 922.5 MHz and beamwidth in xz- and yz-planes is 39.8 and 28 degrees at the center frequency of 2.45 GHz, respectively. This antenna has efficiently high directivity for both bands. The simulation and measurement results are shown.