Microstrip patch antenna array for range extension of RFID applications

In this paper, an UHF band 2X2 microstrip phased antenna array is designed for extending the range of an RFID reader system. The phased antenna array operates at the frequency of 867 MHz, as specified in Gen2 protocol European standards. The phased antenna array has four microstrip patch antennas, three Wilkinson power dividers and a transmission line phase shifter printed on the same Arlon AD450 substrate with a dielectric constant of 4.5 with dimensions of 34x45 cm. The phased array antenna has a measured directivity of 9.5 dB and the main beam direction can be switched between the angles of ± 40 degrees with a 3dB beamwidth of 90 degrees. The phased antenna array can be used to extend the RFID system working range

RFID coverage extension using microstrip-patch antenna array

In this paper, a UHF-band 2 x 2 microstrip phased-array antenna is designed and implemented to extend the coverage of an RFID reader system. The phased-array antenna has four microstrip-patch antennas, three Wilkinson power dividers, and a transmission-line phase shifter. These are printed on a dielectric substrate with a dielectric constant of 4.5. The array has dimensions of 34 cm x 45 cm, operating at a frequency of 867 MHz, as specified in RFID Gen2 protocol European standards. The phased-array antenna has a measured directivity of 12.1 dB, and the main-beam direction can be steered to angles of +/- 40 degrees, with a HPBW of 90 degrees. The phased-array antenna is used as the receiving antenna in a commercial reader system. Experimental results indicate that the coverage of the RFID system with the phased-array antenna is superior to the coverage with a conventional broader-beamwidth microstrip-patch antenna. The proposed system can also be used for a wireless positioning system

A 77 GHz on-chip strip dipole antenna integrated with balun circuits for automotive radar

In this paper, design and implementation of a 77 GHz on-chip strip dipole antenna integrated with both lumped and transmission line based balun circuits are presented. The on-chip antenna is realized by using IHP’s 0.25 μm SiGe BiCMOS technology with localized back-side etch (LBE) module to decrease substrate loss. The strip dipole antenna is fed by both a lumped LC circuit and strip line tapered baluns integrated on the same substrate and occupies an area of 1x1.2 mm2 including the RF pads. For increased directivity, the antenna sits on a grounded silicon substrate. Experimental results show that antenna is well matched around the design frequency and achieves 7 GHz impedance bandwidth (minimum return loss of 17 dB) for the LC balun circuit. The antenna and its feeding structure are well suited for 77 GHz single chip automotive radar applications

A77 GHz on-chip dipole antenna with etched silicon substrate

In this paper, a 77 GHz microstrip dipole antenna is integrated on a layered 11.4 m SiO2 and a silicon substrate with thickness of 670 m. The unbalanced microstrip line is balanced by using a lumped LC circuit balun to feed both of the dipole arms. To decrease the substrate loss and hence increase the antenna gain, Localized Backside Etch (LBE) module offered by IHP is utilized to etch the area under the dipole antenna. For mechanical robustness, two walls of silicon substrate are left at the end of the dipole arms inside the etched area. The simulation results show a 3.2 dBi gain and 15 GHz bandwidth at 77 GHz

Realization of a single-chip, SiGe:C-based power amplifier for multi-band WiMAX applications

A fully-integrated Multi-Band PA using 0.25 μm SiGe:C process with an output power of above 25 dBm is presented. The behaviour of the amplifier has been optimized for multi-band operation covering, 2.4 GHz, 3.6 GHz and 5.4 GHz (UWB-WiMAX) frequency bands for higher 1-dB compression point and efficiency. Multi-band operation is achieved using multi-stage topology. Parasitic components of active devices are also used as matching components, in turn decreasing the number of matching component. Measurement results of the PA provided the following performance parameters: 1-dB compression point of 20.5 dBm, gain value of 23 dB and efficiency value of %7 operation for the 2.4 GHz band; 1-dB compression point of 25.5 dBm, gain value of 31.5 dB and efficiency value of %17.5 for the 3.6 GHz band; 1-dB compression point of 22.4 dBm, gain value of 24.4 dB and efficiency value of %9.5 for the 5.4 GHz band. Measurement results show that using multi-stage topologies and implementing each parasitic as part of the matching network component has provided a wider-band operation with higher output power levels, above 25 dBm, with SiGe:C process

Mikroşerit Yama Dizi Anten ile RFID Sistemlerinde Mesafe Artırımı

Özet: Bu çalışmada, UHF RFID sistemlerinin mesafe ve kapsama alanının artırımına yönelik, çalışma frekansı 867 MHz (Gen 2 Protokol) olan, 2x2 mikroşerit faz kaydırıcılı dizi anten üretilmiştir. Faz dizilimli anten, dört adet mikroşerit yama anten öğesi, üç adet Wilkinson güç bölücüsü ve iletim hattı faz kaydırıcısının dielektrik sabiti 4.50 olan aynı Nelco NH9450 susbtratının üzerine boyutları 34x45 cm olarak basılmıştır. Faz dizilimli mikroşerit dizi antenin yönlülüğü 12,1dB olarak ölçülmüştür ve ana ışıma yönünün ± 30 derece ile anahtarlanabileceği ve 3dB ışıma genişliğinin 93° derece olduğu görülmüştür

SiGe process integrated on-chip dipole antenna on finite size ground plane

This letter investigates the effect of a finite-size ground plane on the radiation pattern and reflection coefficient of a SiGe process integrated on-chip antenna. A flat 77-GHz on-chip strip dipole antenna integrated with a lumped balun circuit is designed and implemented. For increased directivity, the etched silicon substrate is placed on a metal ground plate. The on-chip antenna with the balun circuit is connected to GSG pads for measurement purposes. The antenna is well matched at the original resonance frequency band with 7-12 GHz impedance bandwidth and 4 dBi measured gain at 85 GHz

Anatomical investigations of the Turkish critically endangered species: Achillea sivasica Çelik et Akpulat (Asteraceae)

In this study, the root, stem, leaf midrib and leaf lamina anatomy and achene micromorphology of the Turkish critically endangered endemic Achillea sivasica were investigated for the first time. In this study, the root was found in late primary growth and in early secondary growth stage. It has a large cortex layer consisting of 12-16 cell rows beneath the periderm. Secretory ducts formed by 5-12 secretory cells embedded in the cortex and located near the vascular bundle were found at the root, which was in the early stage of secondary development. The stem was circular-pentagonal in cross-section. There was lamellar collenchyma beneath epidermis of pentagon corners, and cortex parenchyma between corners. Secretory ducts located near the phloem, between the cortex and endodermis on the interfascicular region, were also observed. An endodermis layer was evident and its cells have indentations and protrusions where they touch adjacent endodermis cells, which strengthens the connection between them. In addition, casparian strips were conspicuous in many endodermis cells. The leaf midrib area had a triangular cross section. There were secretory ducts, consisting of 4-5 secretory cells observed on both sides of the sclerenchymatous fibers that accompany the xylem. The leaf lamina was amphistomatic and stomata type was anomocytic. Mesophyll layer was equifacial. There was a large secretory duct and its diameter is bigger than the nearest main lamina vascular bundle. Achene shape of A. sivasica was lanceolate-oblong and its surface was ribbed and glabrous

Fully integrated low-power SiGe power amplifier for biomedical applications

A full-integrated very low-power SiGe power amplifier (PA) is realised using the innovations for high performance, 0.25 mu m SiGe process. The behaviour of the amplifiers has been optimised for the 2.1-2.4 GHz frequency band for a higher 1 dB compression point and high efficiency at a lower supply voltage. The PA delivers an output power of 3.75 and 1.25 mW for 2 and 1 V, respectively. The PA measurements yielded the following parameters: gain of 13 dB, 1 dB compression point of 5.7 dBm, and power added efficiency of 30% for 2 V supply voltage. The PA circuit can go down to 1 V of supply voltage with a gain of 10 dB, 1 dB compression point of 1 dBm, and power added efficiency of 20%. For both supply voltages, the input and the output of the circuit give good reflection performance. With this performance, the PA circuit may be used for low-power biomedical implanted transceiver systems