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Belgrade, Serbia

Radnovic I.,IMTEL Institute | Nesic A.,IMTEL Institute | Milovanovic B.,University of Nis
IEEE Antennas and Propagation Magazine | Year: 2010

This paper presents a new type of turnstile antenna, realized with two crossed dipoles connected in parallel. Feeding of the dipoles in phase quadrature to obtain an omnidirectional radiation pattern is achieved by optimizing their impedances to be complex conjugates. The dipoles are realized with aluminum strips. A balun - the transition from the antenna to a coaxial cable - is accomplished with lumped parameters: two capacitors and two inductors. The concept of the turnstile antenna presented can be used in the VHF and UHF frequency ranges. The measured results show very good agreement with those obtained by simulation. The antenna is also characterized by simple manufacturing and low cost. © 2006 IEEE.

Popovic N.,IMTEL Institute | Ivana R.,IMTEL Institute
Microwave Journal | Year: 2011

This article presents simulated and measured results of a UHF RFID antenna realized with a dipole matched to a CPS (coplanar stripline) and inductively coupled with a small rectangular loop. Such a design enables achieving and controlling high values of the inductive reactance that is necessary for obtaining good match of the antenna to an Application Specific Integrated Circuit (ASIC) chip. The antenna is characterized by a simple and robust design, which results in low-cost realization.

Radnovic I.,IMTEL Institute | Nesic A.,IMTEL Institute | Ilic M.,JP Emisiona Tehnika i Veze | Nesic D.,University of Belgrade
2013 11th International Conference on Telecommunications in Modern Satellite, Cable and Broadcasting Services, TELSIKS 2013 | Year: 2013

The paper presents cavity backed printed antenna with circular polarization (CBACP). The antenna radiating elements are two crossed double bent dipoles that are printed on the dielectric substrate and have complex conjugated impedances. In order to diminish environmental influences the antenna is placed in the metallic cylindrical cavity. By using double bent dipoles the overall antenna dimensions are significantly reduced. CBACP is simulated and realized for operation around 5.9 GHz. Simulated and measured results show good agreement. Furthermore, investigation of cavity parameters and their effect on antenna characteristics has been carried out in order to achieve (a) minimal axial ratio, (b) maximal gain and aperture efficiency and (c) broader axial ratio bandwidth (AR<3 dB). © 2013 IEEE.

Nesic A.,IMTEL Institute | Radnovic I.,IMTEL Institute | Micic Z.,IMTEL Institute | Jovanovic S.,IMTEL Institute
Microwave Journal | Year: 2010

Various factors that limit high side lobe suppression (SLS) in printed antenna arrays (PAA) have been analyzed in this article. A new type of linear printed antenna array, with pentagonal dipoles as radiating elements operating at a second resonance enabling high SLSs, is presented. When operated at the second resonant frequency, the variation of the real and imaginary parts of their impedances with frequency is much slower than in the case with conventional printed patches, which contributes to obtaining high SLSs. The in-phasefeed network for the PAA is realized with symmetrical (balanced) microstrip lines with impedance transformers, enabling tapered feeding of the radiating elements. A second order Dolph-Chebyshev distribution has been used. The SLS obtained in the E-plane of the realized antenna array is better than 34 dB in the range of approximately 26 GHz. In order to achieve a higher gain, that is a narrower beamwidth in the H-plane, the PAA is placed in a corner reflector. The antenna is especially suitable for integration with other passive or active microwave circuits; it is low cost and easy to fabricate.

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