Hossein Saghlatoon

A Dual-Band Low-Profile Aperture Antenna With Substrate-Integrated Waveguide Grooves

This communication presents a new dual-band low-profile aperture antenna with relatively high gain using substrate-integrated waveguide (SIW) corrugated structures. It consists of a cavity excited by a transmission line and four SIW grooves that produce good reflection coefficient and enhanced gain. By designing corrugated structure using constructive superposition of electric fields of patch and grooves, the antenna with high performance in both bands is achieved. In the proposed structure, three simple printed circuit boards (PCBs) for implementing a resonant transmission line and specific SIW structures are employed instead of waveguide feeder and grooves on metallic plate in conventional corrugated antennas. Removing the metallic plate reduces the weight and cost of the structure and provides ease of fabrication. Dual-band characteristic is achieved using resonant slot (cavity) and resonant transmission line. Fabrication results show that the SIW grooves significantly increase the antenna gain with respect to the simple slot antenna.

A novel booster antenna on flexible substrates for metal proximity NFC applications

In this article a novel booster antenna is proposed in order to increase the read range of a small (1.1×10-4 m2) metal mounted HF (13.56 MHz) RFID. The highly inductive coupling between the reader and booster, and between the RFID and booster is the main propagation method. The communication between the reader and RFID realized through the booster antenna. For this purpose two coils are connected in parallel to each other resonating at the same frequency. The greater coil is coupled to the reader antenna and the smaller coil is coupled to the RFID. The simulation and measurement results show the reliability of the proposed structure.

Two-Layered Substrate Integrated Waveguide Filter for UWB Applications

In this letter, an ultra-wideband (UWB) substrate integrated waveguide (SIW) filter using ridge resonator is presented. The filter relies on designing SIW ridge resonator. The comb-shaped resonator makes the filter to be realizable for UWB characteristics. The upper edge of the passband can easily be adjusted by the width of small rod in the ridge resonator. A parametric study is done to show how bandwidths can be adjusted. The measurement results show that a reflection coefficient of better than −14 dB has been obtained over the frequency band of 3.1–10.6 GHz. The maximum insertion loss in passband is almost 1 dB. Moreover, a stopband from 11.4 to 17.4 GHz with a suppression magnitude better than 47 dB has been achieved.

Low-Cost Inkjet Printed Passive Booster for Increasing the Magnetic Coupling in Proximity of Metal Object for NFC Systems

A passive fully inkjet-printed circuit on a plastic based flexible substrate for increasing the communication read range of an NFC based system is proposed. Two parallel coils resonating at 13.56 MHz are used for the improvement of coupling between the transmitter and receiver. The proposed system behaves like a lens by concentrating the absorbed magnetic energy from a wide area in a small focal region. Being a passive circuit, fully inkjet-printed and having only one discrete component made this circuit a very low-cost and tempting solution for improving the magnetic link between transmitter and receiver. Another advantage of this circuit is its operability in proximity of metal asset. Functionality of ordinary systems is severely affected by close metallic objects; hence, having a system that can operate in both conditions is favorable. The measured boosted power after the exploitation of the booster in proximity of the metal asset at 13.56 MHz is 15 dB.

A novel investigation on printed stretchable WLAN antennas

In this paper an investigation on the realizability of the fully printed stretchable antennas has been reported. A novel stretchable conductive ink has been developed and utilized in the printing process. A conductivity of 849 S/cm and stretchability up to 300 % is achieved for the ink. The functionality of the ink at the WLAN band is tested by measuring two bowtie slot and patch antennas. The resonance frequency of the patch antenna shifts from 5.7 GHz to 3.5 GHz by stretching its longitudinal length to 65 % more than its original dimension. It is also feasible to stretch the bowtie slot up to 110 % more than its initial length while its resonance frequency moved from 5.2 GHz to 2.6 GHz. The agreement between the simulation and measurement results show that the proposed ink is very useful for the fabrication of the stretchable RF/Microwave circuits and antennas.

Investigation on Passive Booster for Improving Magnetic Coupling of Metal Mounted Proximity Range HF RFIDs

In this paper, the design methodology, fabrication, and measurement of a passive circuit for increasing the read range of the near-field-communications (NFCs) gadget in handheld devices to read miniature metal mounted radio-frequency identification (RFID) are discussed. Since, the impedances at source and load are unknown, the conventional methods are not helpful for designing a proper communication. The proposed circuit is fabricated on thin flexible polyimide film hence; it can be simply attached to the back of handheld devices with arbitrary shape. Having only one discrete component in the circuit is another step toward low-cost devices. The magnetic coupling between the small metal mounted high-frequency (HF) RFID and the NFC coil are improved by adding two coils connected in parallel to each other resonating at 13.56 MHz. One coil is designed to be coupled to the NFC coil and the other one to the HF RFID. The operability of the system is investigated not only by standard measurement equipment like vector network analyzer but also utilizing different smartphones. The agreement between the simulation and practical results shows that the booster improves the read range significantly.

Low-cost miniaturized open-ended slot-based UHF RFID tag for harsh environment

In this paper, a miniaturized UHF RFID tag is developed for industrial harsh environment applications like oil and gas industries. The tag is designed based on an open-ended slot structure and fed by a primary radiator from the middle. Feeding the antenna using coupling mechanism by a primary radiator results to lower fabrication complexity and costs as well as mechanical durability against continuous vibrations, humidity, water and mud. The whole tag is 0.084λ×0.066λ and can be read up to 5 m in the US band and 3 m in the EU band. By utilization of low cost FR4 substrate alongside the magnetically coupled primary radiator the fabrication costs diminishes significantly. An open-ended slot fed from the middle with bent T-shape pattern for the closed-end and meandered pattern for the open-ended side acts as the antenna and matching circuit together. The measurement results prove the functionality of the designed tag.