Compact Antenna Test Range Research Articles

Compact and simple antenna inspection testing range for 5G smartphones

Abstract Over-the-air antenna performance evaluation in the millimeter-wave band often relies on compact antenna test range systems, which require large reflectors and a substantial measurement range volume. Such setups are impractical for rapid testing in space-constrained environments such as antenna fault diagnosis in smartphone manufacturing facilities. This paper presents a novel design methodology for highly compact antenna inspection testing range utilizing offset parabolic reflectors specifically designed for 5G smartphones. The proposed design system employs three small offset parabolic reflectors configured to account for beam tilting caused by smartphone back covers, eliminating the need to physically reposition the smartphone during testing. By directing electromagnetic fields toward a fixed receiver antenna from multiple angles corresponding to different antenna module positions, the system streamlines the test procedure, significantly reducing measurement time and measurement range volume. The proposed antenna inspection testing range provides a cost-effective and efficient solution for 5G antenna fault diagnosis in manufacturing facilities, ensuring rapid and reliable inspection while minimizing space requirements on the production line.

Evaluation of a double-lens dielectric radome using a microstrip patch antenna for electromagnetic applications

The advancement of increasingly powerful antennas has increased the complexity of radome electromagnetic (EM) design and analysis. The antenna systems are protected from environmental influences by radomes, which are dielectric and electromagnetically transparent structures. Because the presence of the radome affects the performance parameters of the antenna, such as the radiation pattern, reflected power, and side lobe level, its design should not be done independently of the antenna analysis. The great majority of ground-based hemispherical radomes are used for satellite communication antennas, commercial and military radars, telemetry systems, and other uses. Patch antennas, reflector antennas, phased array radars, and other antenna systems are used in these applications. The operational effectiveness of a radome architecture for housing multiple patch antenna systems is proposed and evaluated. The proposed line of work includes antenna-radome interaction analyses, electromagnetic designs for radome walls, and radiation patterns for reflector antennas. COMSOL Multiphysics was used to develop the EM radome and examine the antenna-radome interaction. The findings of a comprehensive analysis into the differences in radiation patterns produced by patch antennas with and without radomes are presented in this article. At a frequency of 1.62 GHz, a plot and investigation of the far-field gain of the microstrip patch antenna with and without radome were done. The radome is estimated to add 0.09 dBi to the gain boost experienced by the microstrip patch antenna.Abbreviations: EM, Electromagnetic; DSF, Dielectric space frame radome; IFR, Induced field ratio; RF, Radio frequency; VSWR, Voltage standing wave ratio; FEM, Finite element method; SRR, Split ring resonator; CATR, Compact antenna test range; DUT, Device being tested; LHM, Left-handed metamaterials; PML, Perfectly matched layer; PTFE, Polytetrafluoroethylene.

Pattern Correction From Nonideal Compact Antenna Test Range Measurement

Pattern Correction From Nonideal Compact Antenna Test Range Measurement

An Accurate Analytical Method to Determine the Range of Quiet Zone in Compact Antenna Test Range

An Accurate Analytical Method to Determine the Range of Quiet Zone in Compact Antenna Test Range

Resistance frequency selection surface framed reflector antenna for 5G OTA measurement

AbstractIndirect far field (IFF) over‐the‐air (OTA) test could be one of the most applicable test methods for 5G mmWave devices. The compact antenna test range (CATR) method has been introduced to the OTA test by 3GPP. Conventional metallic parabolic reflectors without edge treatment can lead to serious edge diffraction which results in high noise and low accuracy. The serrated reflector improves edge diffraction but performs poorly at low frequencies. Reflector antenna with a resistance frequency selection surface (RFSS) frame is proposed for 5G OTA CATR measurement at millimeter frequency, which collimates spherical incident waves into quasi‐plane waves in a relatively short distance, thus forming a quiet zone (QZ) in which large devices under test can be measured in small chamber. In this paper, the reflector with RFSS is investigated through the numerical and experimental methods, it is found that serrated RFSS frame with low edge diffraction could achieve the excellent QZ, which could be helpful in miniaturing CATR chambers for 5G OTA measurement.

A high‐performance dual‐polarized corrugated horn for a compact antenna test range system

AbstractA high‐performance dual‐polarized horn antenna for a 5G millimeter wave compact antenna test range system (CATR) is proposed in this article. The feed antenna is mainly composed of a double‐ridged waveguide junction orthomode transducer (OMT), mode converter, and corrugated horn antenna. Among them, the OMT is the key device for the feed antenna to achieve dual polarization characteristics, and adopts a modular design method to apply the multi‐section impedance transformer in the vertical and horizontal polarization channels with good transmission characteristics. The corrugated horn antenna generates a symmetrical radiation pattern mainly in six corrugated slots. The proposed dual‐polarized corrugated horn antenna impedance matching bandwidth (VSWR < 2) is 24–50 GHz. Moreover, the measured gain is 10–12 dBi, and the measured cross‐polarization level is less than −30 dB within the operating frequency range. Meanwhile, the half‐power beamwidth radiation pattern in the whole operating band has a good symmetry and the beamwidth in both E‐ and H‐plane remains stable. As a practical application, the designed antenna is used as the feed of the CATR system. The measured results show that the amplitude distribution in the quiet zone (QZ) is within ±1 dB, the phase distribution is within ±8°, and the cross‐polarization isolation is better than 27 dB. The performance of the QZ is conducive to the use of the CATR system.

Design and measurements of 6 x 6 m collimator reflector with rounded edges

Compact antenna test range (CATR) is designed to form a plane wave at a small distance from the aperture of the collimator reflector, which allows measurements to be made under far field conditions in a compact anechoic chamber. Currently, collimators are in demand due to the technical re-equipment of the industry for the production of 4G, 5G and Internet of Things stuff. The typical size of a quiet zone for these needs is 1–1.5 m. Along with antenna pattern measurements, collimators are widely used for RCS measurements. In the latter case, the measured objects may have dimensions several times larger than the average size of the quiet zone. Manufacturing, installation and adjustment of collimator reflector of several meters in size is a non-trivial task that requires separate study for each project. An incorrect choice of the reflector geometry can lead to an increase in mass and size, which entails an increase in production costs and the anechoic chamber designed for the CATR. In addition, increase in mass imposes additional requirements on the rigidity of the rack to which the reflector is attached, and the foundation under the collimator. As a rule, large-sized reflectors consist of a dozen fragments, which leads to the need to have special adjustment mechanisms for precision tuning of the reflector fragments. These and other problems need to be solved when developing large CATR. The article presents the issues faced by the LLC «RadioLine» in the process of manufacturing and setting up a collimator stand with a 6 x 6 m reflector. The issues of choosing the geometry of the reflector, its focal length have been highlighted. It has been shown how the agreement of the results of three-dimensional modeling of the reflector and production capabilities has been carried out. The features of the design of the reflector rack are touched upon, in particular, the appropriateness of using two materials: one for the base, and the second for the truss, which is connected to the reflector. After discussing the design features, a scheme for measuring the electromagnetic field distribution in a quiet zone, approaches to improving the quality of the RF characteristics of the CATR have been presented. It is noted that in the process of setting up the collimator, in order to determine the directions to the sources of diffraction, it is useful to apply the recalculation of the measured electromagnetic field in the quiet zone into the plane wave spectrum. At the end of the article, quiet zone cuts have been shown at frequencies of 0.75 GHz, 8.2 GHz and 50 GHz. Average peak-to-peak ripple of the amplitude-phase distribution in the operating frequency range of the CATR is 1 dB in amplitude and 10 degrees in phase.

The Curious Case of Effective Isotropic Sensitivity: Polarization mismatch in over-the-air testing of wireless user equipment

This article provides the theory behind the two-step over-the-air (OTA) test method widely used in 3rd Generation Partnership Project (3GPP) test specifications and, in particular, the testing and characterization of 5G millimeter-wave user equipment (UE) in compact antenna test ranges (CATRs). Special attention is paid to receiver (Rx) characteristics and the polarization mismatch problem, which is encountered in spherical coverage tests. The received power of a UE with a dual-polarized antenna system is derived, and the output signal-to-noise ratio (SNR) is calculated using the maximal ratio combining (MRC) principle. And finally, flaws in the dominant interpretation of this test method in the development of 5G millimeter-wave standards and their consequences are addressed.

Beam‐squint rectified balanced antipodal Vivaldi antenna with sliced fins and quarter‐wavelength labyrinth director

AbstractThis paper introduces a gain‐enhanced, beam‐squint rectified balanced antipodal Vivaldi antenna (BAVA) with symmetrically sliced fins and a novel square‐shaped metallic labyrinth director. The proposed antenna operates from 2 to 18 GHz with S11 less than −10 dB maintaining a fractional bandwidth of 160%, realizes 12.564 dBi as maximum gain at 18 GHz, and achieves greater than 3.415 dBi gain throughout the functioning band of frequency. Improvement of broadside gain by reconfiguration of current loops through symmetric slicing of radiating flares and beam‐squint correction using quarter‐wavelength labyrinth director are addressed by the proposed antenna. The maximum realized size of the antenna is 80 × 40 × 0.508 mm3. Consistent radiation patterns are observed at selected frequencies. Numerical evaluation with a full wave simulation tool and consequent experimental validation with a compact antenna test range is performed.

A novel metasurface lens antenna design for over‐the‐air testing in millimetre wave radio resource management measurement

AbstractIn millimetre wave (mmWave) frequency band, radio resource management (RRM) performance is characterised in plane wave conditions using radiated over‐the‐air test method, which is a challenging combination of protocol and radio frequency performance measurement. This article presents a novel design of multiple lens‐based compact antenna test ranges (CATRs) to simulate multiple angles of arrival from different base‐stations in RRM measurement. Only four lens‐based CATRs are proposed to create plane wave conditions at the device under test with six different angles of arrival and capable of accurately constructing the wireless propagation condition and minimising the diffraction and scattering between adjacent CATRs. The lens‐based CATR is the key element in the RRM measurement system, which is composed of a metasurface lens for phase alignment and a 2 × 2 feed array antenna for the emission of electromagnetic signals. The function and capability of the proposed lens‐based CATR is validated through simulation and measurement, that the worst‐case amplitude variation in the quiet zone region is lower than ±0.8 dB at 26 GHz, and phase variation is lower than ±7.5° in the designed quiet zone, which could be used in the fifth‐generation mmWave RRM measurement.

Theoretical Verification of Single-Reflector Compact Antenna Test Range With High Aperture Usage

In the reflector-based compact antenna test range (CATR), the aperture usage is one of our most concerned problems. Higher aperture usage means that in a CATR with the same aperture reflector, a larger quiet zone (QZ) can be generated to measure a larger aperture antenna. In this work, we theoretically derive a method to design a single-reflector CATR with high aperture usage. Specifically, the radiation function of the ideal feed for the offset-fed CATR is deduced. An offset-fed parabolic reflector CATR with this ideal feed can generate a QZ with 100% aperture usage analyzed by geometrical optics (GO). An offset-fed CATR with a 3 m side-length rectangular aperture parabolic reflector is designed and simulated by physical optics (PO) and physical theory of diffraction (PTD) in GRASP10. With the proposed feed, the aperture efficiency can reach about 74% at 100 GHz and over 86% from 200 to 500 GHz. The simulation results of the QZ field distribution in the system with an ideal feed and a manufactured coaxial cavity horn feed are presented and analyzed. Besides, we also summarize amplitude ripple, phase ripple, and cross-polarization isolation in the QZ to illustrate the performance of the single-reflector CATR.

Verification of the shaped beam feed for high aperture usage efficiency single offset parabolic reflector compact antenna test range

AbstractIn this letter, to verify that the shaped beam feed can enhance the aperture usage efficiency of a single‐offset parabolic reflector compact antenna test range (CATR), a shaped beam horn is proposed. First, we obtain the radiation intensity function of the feed. Then, a coaxial cavity horn feed with a half‐ring is designed to shape the illumination that reaches the main reflector. Measured results demonstrate that, with no edge treatment, the quiet zone size can be up to 75% of the main reflector diameter under 1.20 dB amplitude variations and 12° phase variations at 102.40 GHz, and 70% aperture usage efficiency ranging from 102 to 103 GHz with phase variations less than 12° and amplitude variations less than 1.40 dB. The design verifies that the shaped beam feed can enhance the aperture usage efficiency of a single‐offset CATR.

A Novel Universal Applicability Design Method for Low Cross-Polarization Terahertz Tri-Reflector CATR

In this paper, a novel design approach with universal applicability is proposed for realizing a low cross-polarized terahertz tri-reflector compact antenna test range (CATR). This approach not only enables the radiation direction of the feed relative to the main reflector to be designed arbitrarily but also enables the designed CATR systems corresponding to different feed rotation angles while still maintaining a low cross-polarization. By using the beam mode analysis method and cross-polarization elimination conditions, the geometric configurations of the tri-reflector CATR can be designed for feeds in any different rotation angles, and then according to the kinematic and dynamic ray-tracing method with frequency independence in geometric optics, shaped subreflectors can also be synthesized. Through the above design procedure, four tri-reflector CATRs corresponding to four different feed rotation angles have been achieved, respectively. Numerical simulation results show that the cross-polarizations of four tri-reflector CATRs are all less than –38 dB and the peak-to-peak amplitude (phase) ripples of the quiet zone (QZ) are all within 1 dB (10°) in the frequency range of 100–500 GHz. This demonstrates the effectiveness and universal applicability of the proposed design method in realizing the design of low cross-polarization and good QZ performance for tri-reflector CATRs with different feed rotation angles.

Active 5G radio resource management measurements using a multiple CATR reflector system

AbstractThis paper presents results for active and passive measurements using a novel method based on multiple compact antenna test range (CATR) reflectors to perform simultaneous multiple angle measurements in order to characterize the beam-forming characteristics in a real environment of the 5G devices operating in the millimeter wave frequency band: 24–44 GHz. The over-the-air (OTA) system generates four planar wavefronts with different incidence angles, realizing up to five pairs of angular spreads or four switched/simultaneous angles of arrival. The initial target application is radio resource management (RRM) testing, where the execution of mobility procedures and radio link monitoring of a 5G millimeter wave device are evaluated. The applicability of the multi-reflector approach to RRM testing is measured with commercial 5G handsets, through three test scenarios. The paper demonstrates that baseband (non OTA) testing is not sufficient for RRM FR2, as the results are influenced by the direction of arrival of the signal. It is further shown that OTA testing in a multi-reflector CATR system and a careful selection of a representative set of test directions is critical for full characterization of the performance of a wireless device operating in the millimeter wave bands.

Uncertainties in Bistatic RCS Measurements

Radar Cross Section (RCS) is a far field parameter and limited test range length produces error in its measurements. RCS measured with co-located Tx and Rx antennas is termed as monostatic RCS and with spatially separated Tx and Rx antennas as Bistatic RCS (BRCS). Interest in BRCS measurements has grown due to increase in use of multi-static Radars for detecting low-observable targets. In literature BRCS measurement techniques explored are either horn antenna based far field setups or Compact Antenna Test Range (CATR) based setups. All the techniques have inherent limitations and errors, which need to be assessed as the information generated plays a decisive role in the design of military platforms. In the present paper, the errors in each measurement technique are obtained through extensive numerical computation and measurements on various canonical as well as complex shapes. The results highlight the effect of the phase curvature in either or both, Tx, and Rx paths, affect the measurement accuracies, thereby limiting the target size and highest frequency of operation of present techniques.

Design of a compact antenna test range system based on reflectarray antenna

Design of a compact antenna test range system based on reflectarray antenna

A Wideband Feed Network for Vivaldi Antenna Arrays

A wideband feed network for a Vivaldi antenna array is presented. A limitation of current wideband antenna arrays is the bandwidth of either the feed network or the antenna element. The proposed antenna array consists of four wideband Vivaldi antennas fed with an improved wideband feed network to extend the useable bandwidth of the array. The proposed feed network consists of coplanar waveguide-to-slotline-to-microstrip line transitions. The feed network has a single coplanar waveguide input and four microstrip line output ports. The feed network achieved uniform amplitude and phase balance and an impedance bandwidth of 160% from 1 GHz to 9 GHz. The feed network was used in a uniform linear antenna array to feed four Vivaldi antenna elements. The Vivaldi antenna array achieved stable radiation patterns from 1.3 GHz to 8 GHz, resulting in a useable bandwidth of 144%. The antenna array has a minimum gain of 8 dBi and a maximum of 13.8 dBi within the frequency band. Results for a prototype Vivaldi antenna array, measured in a compact antenna test range, are presented and compared to simulated results from CST Studio Suite.

A review of measurement of electromagnetic emission in electronic product: Techniques and challenges

Nowadays, electronic products are being used extensively in many fields and applications. The dense population of electronic devices in human life has become a challenge for microwave engineers to ensure that their products can meet the Electromagnetic Compatibility (EMC) standards. Complex electronic products with smaller sizes and denser components will be a challenge for compliance with EMC standards. In addition, the occurrence of non-stationary emission at certain operating modes becomes a challenge for analysis. Error in analyzing EM emissions will make the products unable to meet the requirements of EMC standards; hence, they will be prohibited to be marketed. Currently, there are two methods of emission analysis, i.e. by measurement and modeling or computation. There are some problems, however, in the analysis of EM emissions regarding the area of test, complexity, DUT positioning error, installation cost, and time consumption. In this paper, the analysis techniques for EM emissions including Open Area Test Site (OATS), Anechoic chamber, Transverse Electromagnetics TEM Cell, Compact Antenna Test Range (CATR) and near field scanning are reviewed comprehensively. This survey covered EMC standards, principles of EM emission measurement techniques, advantages and disadvantages of EM emission measurement techniques, studies and applications of each technique, recommendations for which technique to be used, and challenges for future research in EM emission measurement. The final section of this paper discusses the challenges for near-field measurements related to the non-stationary emissions phenomenon. This papers also presents the challenges of how to detect and characterize them.

Unified Initial Preprocessing for Phaseless Characterization of Quiet Zone in Millimeter-Wave Compact Antenna Test Range

This letter proposes a unified initial preprocessing technique to address phaseless characterization of a compact antenna test range (CATR) system within millimeter-wave range. With the aid of phase retrieval algorithm, the missing phase information of quiet zone (QZ) can be reconstructed by only two amplitude-only measurements. Here, the initial complex information consists of two parts: back propagation of measurements in QZ as initial amplitude and Zernike-Fourier expansion as initial phase. To further validate the superiority and robustness of the proposed approach, we conduct extensive simulations over the state-of-the-art phase retrieval algorithms under different operating frequencies and compare it to different initial preprocessing methods. In addition to be readily available in practical applications, the proposed technique is also verified under experimental conditions. In a nutshell, this letter paves the way toward the applications of phaseless characterization in CATR system.

A Novel Metasurface Lens Design for Synthesizing Plane Waves in Millimeter-Wave Bands

With the development of communication technology has come several measurement applications requiring plane-wave conditions for wireless-device characterizations in anechoic chambers. In this paper, a metasurface lens with a 2 × 2 feeding-antenna array is proposed and characterized to synthesize a plane wave in a near field for a fifth-generation (5G) millimeter-wave radio-frequency (RF) devices test. The metasurface lens, based on Jerusalem-cross elements printed on a printed circuit board (PCB) substrate, is used for controlling the phase-shift distribution of incident spherical waves. The lens has a size of 0.4 × 0.4 m and is designed to operate at a range from 24.25 GHz to 27.5 GHz, and its feeding-antenna array is located at a focal plane of the lens, which is parallel to the metasurface lens. The lens is studied and verified through simulations and experiments, and a uniform amplitude and phase-field distribution at a reduced distance of 1.2 m generated by the metasurface lens throughout a QZ are achieved. The worst-case amplitude and phase variation of the designed metasurface lens are ±0.75 dB and ±7.5°, respectively. The results show a plane-wave condition can be achieved in 5G millimeter bands through the proposed compact and effective metasurface lens. Moreover, the proposed metasurface lens is shown to be capable of reducing the plane-wave synthesizing distance compared to the compact antenna test range (CATR) with a significantly reduced system cost, making it an attractive alternative to antenna testing in 5G millimeter-wave frequency bands.