Welcome to the AMTA paper archive. Select a category, publication date or search by author.
(Note: Papers will always be listed by categories. To see ALL of the papers meeting your search criteria select the "AMTA Paper Archive" category after performing your search.)
In this paper, we propose quantifying the radiated power of phased arrays or, in general, directive antennas, by the Constrained-View Radiated Power (CVRP). The constrained view shall be interpreted here as the Field-of-View (FoV) of an antenna that defines a region in space where focusing the radiated power is highly desired. In the limiting cases, we have that CVRP equals the Total Radiated Power (TRP) when the FoV covers the whole sphere, while, if the FoV reduces to a single point in space, the CVRP equals the Equivalent Isotropic Radiated Power (EIRP). We further present an analysis based on measured radiation patterns of a 16-element, linearly polarized, millimeter- Wave (mmWave), planar phased array antenna operating at 28 GHz. We compare the results to two ideal planar array antennas with the same number of Huygens and cosine elements. The evaluated figure of merit is computed for different scanning angles, as well as for different malfunctions of antenna elements, both for the real and simulated arrays. The results show that the introduced figure of merit could be potentially used for the detection of malfunctioning elements in antenna arrays as well as to characterize the impact of scan loss. Furthermore, CVRP is useful to straightforwardly and significantly characterize the performance of a directive antenna in terms of the power radiated towards a specific region in space.
In a compact range when the antenna is used for both transmitting and receiving in a monostatic fashion, the wave packet senses everything within its view. An extended long object usually gives rise to a bright reflection (glint) when viewed near its surface normal. To take advantage of this phenomenon, a discrete Fourier transform (DFT) on RCS measurements would yield a spectrum of incident wave distribution along that object, provided the scattering property is uniform along its length. Compared with traditional field-probes which translate a sphere across the test zone in horizontal and vertical directions, this new method extends out from the usual quiet zone, and is faster and less interfering to the field being probed. Inspired by this idea, the progression to practical innovation is discussed.
In General, theoretical RF attenuation in free space is characterized according to the Friis equation in far field range The equation says that the free space propagation of electromagnetic waves is inversely proportional to the square of distance from source It holds only in far field range. We investigate a propagation characteristic of millimeter wave in all ranges of field. The study provides measurement results of free space insertion loss from 20GHz to 90GHz of frequency ranges, where the separation between transmitting and receiving antennas is increased from 1mm to 1400mm with 1mm step. The measurement distances cover all range including the reactive and Fresnel ranges as near field, and the far field too. The measuring values are fitted in the free space path loss factor (λ/4πr)2. There are discrepancies between theoretical and measuring values in near field ranges. We added an extra terms to the formula in order to resolve the difference in near field. The results calculated by new formula are shown in good agreement at Fresnel range and also at some parts of the reactive range. The new formula having the extra terms can be also proposed for antenna gain measurements in the near separation between antennas in the context of results according to this study.
Recently, due to rapid technological changes and the global economic system, conformity assessment for products has become international issue. Major countries have established and implemented standardization and management systems for electrical, electronic, and communication devices, including broadcasting and communication equipment, and manufacturers and consumers who use products and parts demand guarantees that they meet international regulations and required global standards. The Korea Radio Research Agency(RRA)'s Communications Conformity Assessment Center(CCAC) has been conducting performance tests on radio wave test antennas owned by domestic test agencies, but since December 2019, the Korea Accreditation Organization (KOLAS) calibration report issued by the domestic antenna calibration agency has been recognized as a performance test report, and indirect management has been carried out by document inspection of the measured value of the antenna for conformity assessment. Accordingly, a proficient test of antenna performance between the CCAC and the antenna accreditation calibration agencies is promoted to get the measurement reliability of the antenna for radio wave test owned by the designated test agency and maintain the same performance test. The test materials for the proficiency test were sequentially tested by four accreditation calibration agencies for three years using several standard antennas mainly used to measure electromagnetic wavelength, resistance and emission characteristics, and field strength characteristics. The En-Score method, an international standard statistical method used to evaluate proficiency test in the calibration field, was applied to the measurement results between the CCAC and antenna accreditation calibration agencies, and it was determined to be meet in all bands of antenna characteristics. Proficiency test promotes the improvement of test capabilities by verifying and correcting the own test capabilities of designated testing agencies through the development and application of test samples. In this paper, we would like to conduct a proficiency test and analyze the identity of the performance test for indirect management of the antenna performance for the conformity assessment.
Recently, due to rapid technological changes and the global economic system, conformity assessment for products has become international issue. Major countries have established and implemented standardization and management systems for electrical, electronic, and communication devices, including broadcasting and communication equipment, and manufacturers and consumers who use products and parts demand guarantees that they meet international regulations and required global standards. The Korea Radio Research Agency(RRA)'s Communications Conformity Assessment Center(CCAC) has been conducting performance tests on radio wave test antennas owned by domestic test agencies, but since December 2019, the Korea Accreditation Organization (KOLAS) calibration report issued by the domestic antenna calibration agency has been recognized as a performance test report, and indirect management has been carried out by document inspection of the measured value of the antenna for conformity assessment. Accordingly, a proficient test of antenna performance between the CCAC and the antenna accreditation calibration agencies is promoted to get the measurement reliability of the antenna for radio wave test owned by the designated test agency and maintain the same performance test. The test materials for the proficiency test were sequentially tested by four accreditation calibration agencies for three years using several standard antennas mainly used to measure electromagnetic wavelength, resistance and emission characteristics, and field strength characteristics. The En-Score method, an international standard statistical method used to evaluate proficiency test in the calibration field, was applied to the measurement results between the CCAC and antenna accreditation calibration agencies, and it was determined to be meet in all bands of antenna characteristics. Proficiency test promotes the improvement of test capabilities by verifying and correcting the own test capabilities of designated testing agencies through the development and application of test samples. In this paper, we would like to conduct a proficiency test and analyze the identity of the performance test for indirect management of the antenna performance for the conformity assessment.
Recently, due to rapid technological changes and the global economic system, conformity assessment for products has become international issue. Major countries have established and implemented standardization and management systems for electrical, electronic, and communication devices, including broadcasting and communication equipment, and manufacturers and consumers who use products and parts demand guarantees that they meet international regulations and required global standards. The Korea Radio Research Agency(RRA)'s Communications Conformity Assessment Center(CCAC) has been conducting performance tests on radio wave test antennas owned by domestic test agencies, but since December 2019, the Korea Accreditation Organization (KOLAS) calibration report issued by the domestic antenna calibration agency has been recognized as a performance test report, and indirect management has been carried out by document inspection of the measured value of the antenna for conformity assessment. Accordingly, a proficient test of antenna performance between the CCAC and the antenna accreditation calibration agencies is promoted to get the measurement reliability of the antenna for radio wave test owned by the designated test agency and maintain the same performance test. The test materials for the proficiency test were sequentially tested by four accreditation calibration agencies for three years using several standard antennas mainly used to measure electromagnetic wavelength, resistance and emission characteristics, and field strength characteristics. The En-Score method, an international standard statistical method used to evaluate proficiency test in the calibration field, was applied to the measurement results between the CCAC and antenna accreditation calibration agencies, and it was determined to be meet in all bands of antenna characteristics. Proficiency test promotes the improvement of test capabilities by verifying and correcting the own test capabilities of designated testing agencies through the development and application of test samples. In this paper, we would like to conduct a proficiency test and analyze the identity of the performance test for indirect management of the antenna performance for the conformity assessment.
As 5G mobile services keep pursuing higher speeds of data transmission based on the use of mm-Waves, they run across problems. The strength of the mm-Wave signal becomes weak very rapidly as the receiver moves away from the transmitter. To overcome the shortcoming, the antenna takes the form of an array of a large size and is fed by amplifiers along the branches of the power divider. It ends up with growth in size and cost. Metamaterials such as transmitarrays have been proposed to increase the antenna gain avoiding the conventional feed circuitry. A metasurface can play a role of the planar lens which is positioned over the primary source. It leads to enhanced antenna gain and reduction in cost and loss. The antenna performances of the metasurface working for 5G and 6G wireless communication are characterized by measuring the radiated field patterns based on the near-to-far field test method and compact range chamber setup (CATR). The measurements present the results of the two methods are in good agreement and the gain improvement.
Measuring the radiation behavior of antennas in an anechoic environment with far-field (FF) conditions requires large measurement sites resulting in high costs. To overcome this problem, near-field (NF) measurement techniques and nearfield to far-field (NFFF) transformation are used to derive the FF of an antenna under test. Thus, evaluating the accuracy and reliability of the NFFF transformation is highly important. The first step for this evaluation process is creating a valid and accurate reference data library consisting of NF and FF data. NF data is used as input to the NFFF transformation, whereas FF data is used as a reference for comparison to the FF obtained after the transformation. This paper explores analytical studies for different antenna models, namely a pyramidal horn antenna and an open-ended waveguide. Simulations of the models are carried out in a commercial full-wave electromagnetic software, considering the various input parameters influencing the FF results. The NF and FF data from the parameterized simulation model is used to evaluate the NFFF transformation methods. After optimization of the simulation parameters, the required accuracy levels of −30 dB and −40 dB for two different accuracy metrics defined throughout the paper are achieved.
Recent advancements in 3D printing technology have enabled the creation of more precise and accurate antennas, allowing for more complex and innovative designs. With the use of new printers and materials, the cost of producing prototype and customized antennas for specific frequency bands has also decreased. Additionally, 3D printing allows for the creation of single-unit devices to replace traditionally multi-part devices. However, challenges still exist, such as the permittivity of printable materials and the surface roughness of the final prints. In this study, standard gain horns and coaxial adapters were printed and coated to explore these challenges. The gain of the resulting horns has been estimated and compared to derive the performance of different printing materials.
In the past few years, the working group (WG) on antenna measurements, being part of the European antenna and propagation association (EurAAP), has spent a great deal of effort in carrying out a whole range of antenna measurement related activities and projects. These activities cover various areas of antenna measurements and are sub-divided into different tasks, such as measurements and comparisons of reference antennas, revisions of IEEE antenna measurement standards, self-assessment measurements of facilities, and emerging techniques for antenna over-the-air (OTA) measurements. This paper gives an update of the status of these activities carried out by the EurAAP WG on antenna measurements including the initial of a new campaign based for a first time on a low directive antenna, an MVG SMC2200 monocone antenna on a circular ground plane. Moreover, the new activities in collaboration with the EurAAP WG on software and modeling tools will be presented with the aim of promoting the benefits of the synergy between measurement and simulation modeling tools.
In 6G wireless communication systems, the use of array antennas and metamaterial reflectors above 100 GHz is being considered to expand the communication area, and there is an urgent need to establish a high-precision evaluation system for array antennas and metamaterial reflectors, which are key components for 6G wireless systems. To meet these demands, we have developed a compact antenna test range (CATR) system using offset Gregorian antennas, which consists of a parabolic mirror and an ellipsoidal mirror, to evaluate the radiation patterns of antennas and RCS patterns of metamaterial reflectors in the 100 GHz to 300 GHz band. The double-mirror configuration has the advantage of shortening the distance between the parabola and the antenna to be evaluated, since a long focal length can be achieved in a small space. In this presentation, we report on the performance of the developed offset Gregorian compact range system and the evaluation results of the antenna and reflector. So far, we have succeeded in generating a uniform plane wave at a distance of about 1 m from the parabolic surface in an area including a circle with a radius of 400 mm. The amplitude difference is less than 0.7 dB compared to the antenna radiation pattern measured by the planer near-field measurement system. The amplitude uniformity and phase variation of the generated plane wave are reported.
The Naval Surface Warfare Center Indian Head Division (NSWC IHD) EOD Technology Center is a United States Navy facility with the urgent mission of supporting the Department of Defense (DoD) warfighter in the detection and neutralization of unexploded ordnance (UXO) and improvised explosive device (IED) threats. The Radio Frequency (RF) Laboratory at NSWC IHD, is centered around its 24’ by 12’ by 12’ anechoic chamber, which was designed mainly for antenna measurement. However, the unique challenges this department was tasked to resolve has resulted in varied and uncommon uses of the chamber. The chamber, RF test equipment and staff of electrical engineers, mechanical engineers and computer scientists, have participated in the automated RF testing of X-ray equipment, bomb suits, radars, electronic jammers and IEDs, to provide just a partial listing of test events. This paper will detail recent unique assignments that required the rapid research, design, development and implementation of automated RF test and measurement systems providing solutions for the EOD community. The anechoic chamber’s system uses, from antenna design and measurements, materials testing, electromagnetic compatibility (EMC) testing to electronic warfare (EW) testing of radars and jammers, will be discussed along with the examination of the software algorithms that enabled fast, repeatable and reliable RF measurements. Focus will be on the roles electromagnetic (EM) measurement has for EOD robotics, EW system development and IED threat understanding. The authors speak from the diverse backgrounds of electrical and mechanical engineering and computer science.
The Naval Surface Warfare Center Indian Head Division (NSWC IHD) EOD Technology Center is a United States Navy facility with the urgent mission of supporting the Department of Defense (DoD) warfighter in the detection and neutralization of unexploded ordnance (UXO) and improvised explosive device (IED) threats. The Radio Frequency (RF) Laboratory at NSWC IHD, is centered around its 24’ by 12’ by 12’ anechoic chamber, which was designed mainly for antenna measurement. However, the unique challenges this department was tasked to resolve has resulted in varied and uncommon uses of the chamber. The chamber, RF test equipment and staff of electrical engineers, mechanical engineers and computer scientists, have participated in the automated RF testing of X-ray equipment, bomb suits, radars, electronic jammers and IEDs, to provide just a partial listing of test events. This paper will detail recent unique assignments that required the rapid research, design, development and implementation of automated RF test and measurement systems providing solutions for the EOD community. The anechoic chamber’s system uses, from antenna design and measurements, materials testing, electromagnetic compatibility (EMC) testing to electronic warfare (EW) testing of radars and jammers, will be discussed along with the examination of the software algorithms that enabled fast, repeatable and reliable RF measurements. Focus will be on the roles electromagnetic (EM) measurement has for EOD robotics, EW system development and IED threat understanding. The authors speak from the diverse backgrounds of electrical and mechanical engineering and computer science.
The IEEE Std 1720™, "Recommended Practice for Near-Field Antenna Measurements," serves as a dedicated guideline for conducting near-field (NF) antenna measurements [1]. It serves as a valuable companion to IEEE Std 149-2021™, "IEEE Recommended Practice for Antenna Measurements," which outlines general procedures for antenna measurements [2]. IEEE Std 1720 was originally approved in 2012 as a completely new standard by the IEEE Standards Association Standards Board. It holds significant importance for users engaged in NF antenna measurements and contributes to the design and evaluation of NF antenna measurement facilities. With its tenyear term coming to an end in 2022, the standard will no longer remain active. Nonetheless, a "minor revision" of the existing standard is in progress and is expected to be completed in 2023. The objective of this paper is to provide insights into the ongoing activities surrounding the revision and to explore the proposed changes. It aims to facilitate a discussion on the modifications to and their implications for modern NF antenna measurements.
This communication provides an effective two-steps strategy to compensate for known 3-D probe positioning errors occurring in the non-redundant (NR) cylindrical near-to-far-field (NTFF) transformations. As first step, a phase correction, here denoted as cylindrical wave correction, is employed to perform the correction of the positioning errors relevant to the deviations of the measured NF samples from the nominal scanning cylinder. Then, an iterative procedure will be applied to retrieve the NF samples at the points specified by the adopted sampling representation from those obtained at the previous step and affected by 2-D positioning errors. Finally, after properly reconstructing the correctly distributed cylindrical samples, the data necessary to apply the classical cylindrical NTFF transformation can be restored in accurate way by employing a 2-D optimal sampling interpolation (OSI) formula. It should be noticed as, to derive the NR sampling representation, as well as the OSI scheme, it is necessary to provide a proper modeling of the antenna under test. This modeling has been got by shaping the source with a prolate spheroid. Numerical tests will show the capability of the procedure to compensate these 3-D positioning errors.
This work aims to propose and optimise a non-redundant spherical spiral near-to-far field (NTFF) transformation for elongated AUTs from spiral near-field (NF) data acquired over the upper hemisphere due to the presence of an infinite perfectly electric conducting (PEC) ground plane. Such a technique properly exploits the principle of image and the theoretical foundations of spiral scan for non-volumetric AUTs to develop the non-redundant representation along the sampling spiral in presence of PEC ground plane and to synthesise the voltage NF data which would be acquired over the spiral wrapping the lower hemisphere. Once these voltage NF data have been synthesised, then an efficient 2-D optimal sampling interpolation scheme allows the recovering of the NF data required by the classical NTFF transformation. In the hypothesis that the AUT and its image exhibit a predominant dimension as compared to the other two ones, a prolate spheroidal source modeling is here adopted. Numerical tests show the accuracy of the developed non-redundant spherical spiral NTFF transformation.
Demand for broadband connectivity in moving platforms on land, sea, and air has opened the mass market for low-cost mobile ground-station terminals that employ electrically steerable antennas. The antennas of these terminal units need to be tested in a production line environment. Planar near-field scanning is considered as a convenient measurement method, but the time needed for conventional scanning may be prohibitive. In this paper, the design of a multiprobe planar near-field scanner for rapid antenna testing at Ku-band is presented. A probe array is moved along a spiral path to avoid large accelerations and decelerations of the probe array, and the near-field sampling is done simultaneously with multiple of respective receivers. Thus, the data acquisition time is significantly reduced compared to the single probe or receiver measurement. A preliminary antenna testsystem design for the mobile ground-station terminal antennas operating at Ku-band is presented. The numerical results for simple representative antenna models suggest good performance of the system.
Antennas fully integrated in radar systems or even on the chip packages cannot be measured with a conventional antenna measurement system as there is no access to the antenna feed point. The two-way radiation pattern of a frequency modulated continuous wave (FMCW) radar system can be measured using the transmit and receive module of the radar itself while measuring against a reflector. Still, the measurement uncertainty differentiates from conventional antenna measurements, and detailed studies are missing. The uncertainty factors introduced by the mechanical system and the reflectors themselves like the size of the reflector and the mechanical misalignment of the reflector and antenna under test (AUT) are investigated within this study on the basis of simulations. As reference antenna the simulation model of a scalar feed horn antenna and a plate, a dihedral and a trihedral reflector are used. The results show an overall stable behavior and a low error for the evaluated mechanical misalignments.
First realizations of reconfigurable intelligent surfaces (RIS) are becoming available as research on 6G advances. Consequently, prototypes have to be characterized by means of radiation pattern measurements to confirm the design properties. The main challenges here are the degrees of freedom from independent receiver and transmitter location in combination with surface configurations. We propose a far-field to nearfield measurement setup to conduct first full-sphere CATR measurements of a 5 GHz RIS at RWTH Aachen University. In order to cope with parasitic effects of the near-field probe, applicable post-processing methods including time gating and reconstructed equivalent currents are applied and evaluted.
In this paper, we thoroughly test and validate the complete active signaling measurement setup using a Plane Wave Generator (PWG), Radio Communication Tester (RCT), and a well-known antenna standard. The results of our study demonstrate excellent agreement between the Equivalent Isotropic Radiated Power (EIRP) measurements obtained using the active setup with the PWG, and those obtained using a passive measurement system employing the multiple probe spherical near-field technique. Furthermore, the Total Radiated Power (TRP) values derived from the active setup with the PWG are within expected uncertainty to the measured conducted power at the Horn input port. The measurements are done at 28GHz. The measured TRP using active OTA and conducted measurements are within 0.31 dB (6.9%) difference. This robust comparison illustrates the reliability and confidence in utilizing the PWG-based active measurement system.