Aleksandar Nesic

Printed Planar 8

A new type of printed millimeter planar antenna with circular polarization for 60-GHz range is proposed. Radiation elements with two open tape rings are arranged in a two-dimensional 8×8 antenna array. Feeding is synphase network with tapered symmetrical (balanced) microstrip in the same plane as the radiation elements. The 8×8 array is fabricated in the conventional technology. To test reproducibility, three samples are fabricated. Measured S11 (VSWR), gain, and axial ratio (AR) are very good and in very good agreement between all three samples: AR<;3 dB about 25% and gain near 20 dBi.

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Different types of printed antennas for millimeter ranges such as high gain (narrow beam) with linear and circular polarization, sector antennas with azimuth angle of 60/spl deg/, 90/spl deg/ and 180/spl deg/, and omnidirectional antennas are proposed. All types are suitable for integration with active microwave and millimeter wave amplifiers, and down and upconvectors. Also, the proposed sector and omnidirectional antennas are practically applicable for the lower microwave range of 5 GHz that is included in the new generation of communication systems for 60 GHz range.

8 Array Antenna With Circular Polarization for Millimeter-Wave Application

The paper presents a new type of turnstile antenna realized with two crossed dipoles parallelly connected. Feeding of the dipoles in phase quadrature to obtain omnidirectional radiation pattern is achieved by optimizing their impedances to be complex-conjugated. Dipoles are realized with aluminum strips. Balun - transition from the antenna to coaxial cable - is accomplished with concentrated parameters - two capacitors and two inductors. Presented concept of the turnstile antenna can be used in VHF and UHF frequency ranges. Measured results show very good agreement with those obtained by simulation. The antenna is also characterized by simple manufacturing and low cost.

Antenna solution for future communication devices in mm-wave range

In this paper, we introduce new millimeter-wave corner antenna arrays (MWCA) with eight axially placed printed dipoles fed by an integrated symphase network. The antenna array is placed between two metal plates that make the corner reflector. The antennas were simulated and realized in the frequency range about 26 GHz, which is popular for microwave communication networks. Three antennas, with different H-plane beamwidths (intended for azimuth) of 55deg, 110deg, and 180deg, were investigated, simulated, and realized. The bandwidths of all of the antennas were wider than 12%. The losses in all of the antennas were less than 1 dB. The agreement between simulated and measured results was very good. Millimeter-wave corner antenna arrays are low in cost and very simple to realize, and are also suitable for integration

A New Type of Turnstile Antenna

Side lobe suppression of printed antenna arrays with perpendicular reflector has been analyzed in this article. The arrays are with pentagonal dipoles as radiating elements operating at a second resonance. The used distribution is chosen to enable high side lobe suppressions bigger than 41.5 dB at the frequency of 12 GHz. The feeding network in symmetrical (balanced) microstrip technique with impedance transformers is presented too. The antenna arrays with the high side lobe suppression are very sensitive in small deviation of distribution coefficients from ideal that can results in decreasing SLS values. Therefore, the optimal feeding network with minimal departure from determined distribution is investigated.

Millimeter-wave printed antenna arrays for covering various sector widths - [Antenna Designer's Notebook]

The detailed research, full development, and experimental realization of a new printed antenna array with cosecant squared-shaped beam pattern are presented. Some advantages of proposed antenna, as compared to previously realized microstrip cosecant-squared pattern antennas, are pointed out. The suggested antenna, which targets X frequency range, has significantly better bandwidth characteristics thanks to its symmetrical radiating elements of pentagonal shape. The symmetrical feeding network of impedance transformers provides necessary amplitudes and phases distributions obtained by Orchard Elliotts methods and genetic algorithm. Furthermore, it is on the same substrate as antenna, making entire concept simple, easy, and cheap for realization. Moreover, the antenna is in a corner reflector, which enables achieving relatively high gain. The proposed antenna is validated by simulations and measurements. The measured radiation pattern barely varies from theoretical radiation pattern. Realized antenna has gain above 15 dBi and sidelobe suppression greater than 20 dB at the center frequency of 10 GHz.

Side lobe suppression of printed antenna array with perpendicular reflector

Concept, simulation, design and realization of the printed tapered antenna array with a subreflector and a cylindrical-parabolic reflector is presented. This antenna is intended for microwave and millimeter wave ranges and is characterized by many advantages such as efficacy, compactness and possibility of integration with other passive and active microwave circuits. Antenna gain is nearly 26 dBi and aperture efficiency is almost 50%. The antenna operates in the frequency range around 26 GHz. Measured results are in good accordance with those obtained by a simulation.

Design, Realization, and Measurements of a Corner Reflector Printed Antenna Array With Cosecant Squared-Shaped Beam Pattern

In this paper new types of (1-D) microstrip photonic band-gap (PBG) filters are presented. They have sinusoidal variation of the characteristic impedance in function of the length along the microstrip line. They are, also, without etching in the ground plane. Band-stop, band-pass and low-pass filters are simulated, realized and measured. Band-stop filters give only one band-gap (without harmonic response). Band-pass and low-pass filters are serial connections of two or three band-stop filters and give very good characteristics. Agreement between simulation and measurement is very good.

High side lobe suppression millimeter wave antenna with a cylindrical-parabolic reflector

We present a novel design of frequency-scanning array antenna which consists of eight antiresonant dipoles fed by balanced microstrip line. Feeding network contains four elongated split-ring resonators (SRRs) placed between dipoles to increase the frequency dependant phase difference between radiating elements. Split-ring resonators are with gap parallel and far from microstrip line that provides better matching in a wider frequency range in comparison to the similar SRRs with gap close to microstrip line. The beam scanning is found to be Δ=36° with frequency variation in the range from 5.7GHz to 6.1GHz and a very flat gain between 12.5 and 13.6dBi.

1-D Microstrip PBG Filters Without Etching in the Ground Plane and with Sinusoidal Variation of the Characteristic Impedance

Concept of design and realization of high gain printed antenna structures is presented. They consist of antenna array, subreflector, feeding network and bal-un, all printed on the same dielectric substrate. Linear array is positioned on the axis focus of the cylindrical parabolic reflector. Results are presented for the range around 26 GHz with side lobe suppression (SLS) of 30 dB as well as for the range around 60 GHz. An example of design, optimization and realization of the high gain antenna around 23 GHz with cylindrical-parabolic reflector is given in the second part of the paper. In all reported cases agreement between simulated and measured results is very good.