HARA TERIZATION OF TWO LOGARITHMI PERIODI ANTENNAS …
1
Results We show the radiaon paerns obtained with 4nec2 and experimentally. The condions of the simulaon is ideal because the program only takes into account the signal a fix value of the signal to receive, i.e. 481.76 MHZ and considers all opmal design parameters for this type antenna. (a) (b) Fig. 3. (a) Blue line represents the radiaon paern obtained using 4nec2, red line is obtained radiaon paern in CONIDA. (b) Blue line represents the radiaon paern obtained using 4nec2, red line is obtained radiaon paern in Punta Lobos. (a) (b) Fig. 4. Radiaon paern in Cartesian coordinates. Blue radiaon paern obtained using the program 4nec2, black radiaon paern obtained using the spectrum analyzer. (a) CONIDA. (b) Punta Lobos The radiaon paern is obtained with 4nec2 is more definite wider than the experimentally obtained due to the design parameters are well controlled by the program; while experimentally not have those details, besides the anten- na was exposed to interference from other signals and that does not happen with the simulaon. Also menon that the recepon signal IRTP was not the only one who caught the spectral analyzer.. The beam width at -3 dB obtained experimentaly is 43 ° for CONIDA site and 40° for Punta Lobos site. CHARACTERIZATION OF TWO LOGARITHMIC PERIODIC ANTENNAS OF THE STATIONS e-CALLISTO IN PERU SAN ISIDRO AND PUNTA LOBOS V. Loaiza Tacuri, J. Rengifo G., W. Guevara Day Comisión Nacional de Invesgación y Desarrrollo Aeroespacial (CONIDA) – Agencia Espacial del Perú In order to implement e-CALLISTO staons in Perú, to performed the first test measurements of signal recepon and monitoring of the Sun, with a system that consists of a spectral analyzer and a logarithmic periodic antenna of 23 elements. The sensivity of the antennas were characterized by determining the radiaon paern and the corresponding beam width. These tests were performed in two sites: San Isidro, Lima – Peru, where currently the staon is installed and at Punta Lobos, Lima – Perú, scienfic site of the Comisió ́ n Nacional de Invesgación y Desarrollo Aeroespacial (CONIDA). Furthermore, it presents the simulaon of the logarithmic periodic antenna of 23 elements which gets the radiaon paern and the beam width, to compare them with results obtained from the characterizaon of the same. Introducon e-CALLISTO (Compound Astronomical Low-Cost Low-frequency Instrumental for Spectroscopy and Transportable Observatory) is a world network of spectrometers, antennas and a low noise amplifier (LNA 33LN-ZX60-S), the spectrometer uses a computer to store the data, whose purpose is the sun observaon for 24 hours and study solar bursts that occur in the upper solar corona. For this reason that a staon CALLISTO was installed in Peru as it covers schedule interval from 11 to 23 UT connuosly all the year. The radiaon paern and beamwidth of a log-periodic antenna used as a receiver in the e-callisto staons they play a main roll, because these parameters allow properly orient the antenna to a parcular region. The radiaon paern is a diagram that shows the variaon of the power radiated by an antenna how funcon of its direcon. The beamwidth is the angle between the points where the signal strength is half of its maximum radiated power that is -3dB from the calculated maximum power of the radiaon. For that the present work has for goal is characterize a logarithmic periodic antenna of 23 dipolos for the staon e-CALLISTO in Peru obtaining its radiaon paern and calculang its beamwidth. The logarithmic periodic antenna we use has a frequency range of operaon 70 - 1000 MHz and the frequency range of the spectrometer is 45 to 870MHz. Methodology and Instrumentaon To find the radiaon paern and beamwidth of the antennas we used as follows: For the simulaon with 4Nec2, first we designed the antenna with the values of the lengths of the dipoles, the distance between dipoles (measures previously), impedance of 50 Ohms; while the values of τ=0.93 (constant design) and σ=0.70 (relave spacing of dipoles) design features that are assigned by 4Nec2. With all these consideraons, the simulaon of the antenna for the frequency 481.76 MHz, provided the values of the maximum power for each direcon. Fig.1. At the leſt the log-periodic antenna designed with the right program and 4nec2 the log-periodic antenna located on CONIDA office. To measure the real values of the maximum powers of receipt of the log- periodic antenna, the antenna was connected to the spectrum analyzer whose signal capture was centered at a frequency of 481.76 MHz, this signal is emied by the repeater antenna of the Naonal Instute of Radio & Television of Peru - IRTP *4+, located in the Cerro Marcavilca Chorrillos of the district of at an altude of 278msnm. We oriented the antenna horizontally from the largest to the smallest dipole heading for Mount Marcavilca located at a distance of 8.3 km from the test site (CONIDA - San Isidro), Once IRTP signal (481.76 MHz) captured with oriented in that direcon antenna grasp the maximum power reaches the antenna and from that point we turn the antenna in steps of 10 ° to 360 ° sweep. Fig. 2 The picture shows the antenna IRTP located 8.3 km distance from the CONIDA where measurements with the equipment shown in the right image of the figure was made. Logarithmic Periodic Antenna 23 dipoles. 4nec2 Program in which the antenna is designed for simulaon Spectral Analyzer Conclusions It was possible to obtain the of radiaon paern of the periodic logarithmic antenna of 23 dipolos with the data obtained by simulaon and measures using an analyzer of spectrum. Beamwidth antenna was determined using the radiaon paern obtained from the simulaon data and the data measured with the instrument, but with the difference that the beamwidth obtained simulaon is greater than that obtained with the measured values. It is not necessary to move the antenna when this orientated vercally for the solar observaon due to that the beamwidth covers the step of the Sun during the hours of observaon. References *1+ Thomas L. Wilson, Kristen Rohlfs, Susanne Hüemeister (2009). Tools of Radio Astronomy. Fiſth Edion. Springer *2+ The ARRL Antenna Book R. Dean Straw (2007) 21st edion. Radio Amateur’s Library. *3+ 4Nec2 program: hp://www.qsl.net/4nec2/ *4+ hp://comunicaciones.mtc.gob.pe/frecuencias/Television.aspx Acknowledgment Would like thank to Luis Oniano Ormachea.
Transcript of HARA TERIZATION OF TWO LOGARITHMI PERIODI ANTENNAS …
Results
We show the radiation patterns obtained with 4nec2 and experimentally. The conditions of the simulation is ideal because the program only takes into account the signal a fix value of the signal to receive, i.e. 481.76 MHZ and considers all optimal design parameters for this type antenna.
(a) (b) Fig. 3. (a) Blue line represents the radiation pattern obtained using 4nec2, red line is obtained radiation pattern in CONIDA. (b) Blue line represents the radiation pattern obtained using 4nec2, red line is obtained radiation pattern in Punta Lobos.
(a) (b) Fig. 4. Radiation pattern in Cartesian coordinates. Blue radiation pattern obtained using the program 4nec2, black radiation pattern obtained using the spectrum analyzer. (a) CONIDA. (b) Punta Lobos
The radiation pattern is obtained with 4nec2 is more definite wider than the experimentally obtained due to the design parameters are well controlled by the program; while experimentally not have those details, besides the anten-na was exposed to interference from other signals and that does not happen with the simulation. Also mention that the reception signal IRTP was not the only one who caught the spectral analyzer.. The beam width at -3 dB obtained experimentaly is 43 ° for CONIDA site and 40° for Punta Lobos site.
CHARACTERIZATION OF TWO LOGARITHMIC PERIODIC ANTENNAS OF THE STATIONS e-CALLISTO IN PERU SAN ISIDRO AND PUNTA LOBOS
V. Loaiza Tacuri, J. Rengifo G., W. Guevara Day
Comisión Nacional de Investigación y Desarrrollo Aeroespacial (CONIDA) – Agencia Espacial del Perú
In order to implement e-CALLISTO stations in Perú, to performed the first test measurements of signal reception and monitoring of the Sun, with a system that consists of a spectral analyzer and a logarithmic periodic antenna of 23 elements. The sensitivity of the antennas were characterized by determining the radiation pattern and the corresponding beam width. These tests were performed in two sites: San Isidro, Lima – Peru, where currently the station is installed and at Punta Lobos, Lima – Perú, scientific site of the Comisió́n Nacional de Investigación y Desarrollo Aeroespacial (CONIDA). Furthermore, it presents the simulation of the logarithmic periodic antenna of 23 elements which gets the radiation pattern and the beam width, to compare them with results obtained from the characterization of the same.
Introduction
e-CALLISTO (Compound Astronomical Low-Cost Low-frequency Instrumental for Spectroscopy and Transportable Observatory) is a world network of spectrometers, antennas and a low noise amplifier (LNA 33LN-ZX60-S), the spectrometer uses a computer to store the data, whose purpose is the sun observation for 24 hours and study solar bursts that occur in the upper solar corona. For this reason that a station CALLISTO was installed in Peru as it covers schedule interval from 11 to 23 UT continuosly all the year.
The radiation pattern and beamwidth of a log-periodic antenna used as a receiver in the e-callisto stations they play a main roll, because these parameters allow properly orient the antenna to a particular region. The radiation pattern is a diagram that shows the variation of the power radiated by an antenna how function of its direction. The beamwidth is the angle between the points where the signal strength is half of its maximum radiated power that is -3dB from the calculated maximum power of the radiation.
For that the present work has for goal is characterize a logarithmic periodic antenna of 23 dipolos for the station e-CALLISTO in Peru obtaining its radiation pattern and calculating its beamwidth. The logarithmic periodic antenna we use has a frequency range of operation 70 - 1000 MHz and the frequency range of the spectrometer is 45 to 870MHz.
Methodology and Instrumentation
To find the radiation pattern and beamwidth of the antennas we used as follows:
For the simulation with 4Nec2, first we designed the antenna with the values of the lengths of the dipoles, the distance between dipoles (measures previously), impedance of 50 Ohms; while the values of τ=0.93 (constant design) and σ=0.70 (relative spacing of dipoles) design features that are assigned by 4Nec2. With all these considerations, the simulation of the antenna for the frequency 481.76 MHz, provided the values of the maximum power for each direction.
Fig.1. At the left the log-periodic antenna designed with the right program and 4nec2 the log-periodic antenna located on CONIDA office.
To measure the real values of the maximum powers of receipt of the log-periodic antenna, the antenna was connected to the spectrum analyzer whose signal capture was centered at a frequency of 481.76 MHz, this signal is emitted by the repeater antenna of the National Institute of Radio & Television of Peru - IRTP *4+, located in the Cerro Marcavilca Chorrillos of the district of at an altitude of 278msnm.
We oriented the antenna horizontally from the largest to the smallest dipole heading for Mount Marcavilca located at a distance of 8.3 km from the test site (CONIDA - San Isidro), Once IRTP signal (481.76 MHz) captured with oriented in that direction antenna grasp the maximum power reaches the antenna and from that point we turn the antenna in steps of 10 ° to 360 ° sweep.
Fig. 2 The picture shows the antenna IRTP located 8.3 km distance from the CONIDA where measurements with the equipment shown in the right image of the figure was made.
Logarithmic Periodic Antenna 23 dipoles.
4nec2 Program in which the antenna is designed for simulation
Spectral Analyzer
Conclusions
It was possible to obtain the of radiation pattern of the periodic logarithmic antenna of 23 dipolos with the data obtained by simulation and measures using an analyzer of spectrum.
Beamwidth antenna was determined using the radiation pattern obtained from the simulation data and the data measured with the instrument, but with the difference that the beamwidth obtained simulation is greater than that obtained with the measured values.
It is not necessary to move the antenna when this orientated vertically for the solar observation due to that the beamwidth covers the step of the Sun during the hours of observation.
References
*1+ Thomas L. Wilson, Kristen Rohlfs, Susanne Hüttemeister (2009). Tools
of Radio Astronomy. Fifth Edition. Springer
*2+ The ARRL Antenna Book R. Dean Straw (2007) 21st edition. Radio
Amateur’s Library.
*3+ 4Nec2 program: http://www.qsl.net/4nec2/
*4+ http://comunicaciones.mtc.gob.pe/frecuencias/Television.aspx
Acknowledgment
Would like thank to Luis Otiniano Ormachea.
