Active Phased Array Antenna Research Articles

THE METHOD OF CALCULATION OF COEFFICIENTS OF THE PHASE ABERRATIONS OF AXIALLY ASYMMETRIC DUAL REFLECTOR ANTENNAS

Aerodrome-enroute surveillance radar systems (ARSR) of civil aviation are designed for detection of aerial objects and determination of their range and movement parameters. Meanwhile, the reflector-type antennas are still the main type of_used antenna systems. Radars (ARSR) have, as a rule, antennas with a bidirectional beam, structurally reflector-type antenna is made in the form of a truss welded structure. The use of active phased antenna arrays (APAR) is a promising direction of radars (ARSR) development. Radars (ARSR) based on the phased antenna arrays can significantly improve such critical tactical and technical criteria as: the accuracy of the coordinates determination, the number of simultaneously followed targets. However, the use of APAR does not solve one of the main problems - the presence of a support-rotary device in the radar (ARSR). The principal necessity of a support-rotary device leads to the need of the use of movable joints of feeder lines, which, with a significant number of antenna elements used in the PAR, significantly reduces the potential time before failure. It seems promising to use in the radar antenna systems based on several stationary multi-beam dual-reflector antennas made by axially asymmetric scheme. Methodology of estimation of aberrations of a dual-reflector sensimetrics antenna based on a polynomial expansion of the eikonal function in the plane of the aperture of the main reflector is proposed in the article. Analytical expressions of the functions of display and rotation of the scanning plane of a dual-reflector axially asymmetric antenna with arbitrary parameters, designed based on clippings from centrally symmetric surfaces of rotation of the second order, are obtained. It is shown that the aplanatic antennas lose their scanning features during the transition to the axially asymmetric variant.

Efficient integration of scalable active‐phased array antenna based on modular approach for MM‐wave applications

AbstractIn this article, efficient integration approach of building large‐scale active‐phased array antenna (A‐PAA) for millimeter‐wave (mm‐wave) is presented. In this approach, large‐scale A‐PAA is constructed from smaller size A‐PAAs (modules) with inter‐element spacing of half‐wave length and assembled into efficient planar waveguide feeding platform based on substrate integrated waveguide (SIW) technology. Simple low profile vertical RF‐connection between the SIW splitter/combiner outputs and the modules using surface mount super‐mini board‐to‐board (SM‐SMC) is presented. Embedded metallic via‐pad transition integrated into the SIW board is employed to match the SM‐SMC to the SIW mode at Ka band. Sixteen‐way power splitter with transitions to SM‐SMCs is designed at 30 GHz. The measured results of S‐parameters show insertion loss of <0.70 dB over the operating frequencies 28.50‐30.50 GHz.

USE OF AN ACTIVE PHASED ARRAY ANTENNA IN RADAR’S SIDE LOBES CANCELLATION SYSTEM

The paper describes an example of designing the radar’s side lobes cancellation system. It is based on the scheme of one channel interference canceler. The analysis of the antennas, which are ussually used in radar’s side lobes cancellation systems, is done, and active phased array antenna is chosen as an antenna of the radar’s side lobes cancellation system. The array pattern was formed by using antenna synthesis iterative method in order to fulfill the radar’s side lobes cancellation system’s antenna requirements. The antenna modeling results and its’ analysis are presented. The radar’s side lobes cancellation system with active phased array antenna eliminates intentional noise or impulse interference from any side lobe directions of the radar antenna.

A Multiple Element Calibration Algorithm for Active Phased Array Antenna

In this paper, we investigate an octagonal phase settings algorithm for multiple k th elements in improving the calibration techniques for an active phased array antenna using the power measurement output of each element. An active phased array antenna calibration requires simultaneous measurement of each antenna element of an array to guarantee high target precision to meet a specific operation. Therefore, each element in the active phased array antenna requires an efficient and accurate amplitude and phase variation in order to calibrate the array antenna system power output with the excitations of the antenna elements using linear equations to adjust the corresponding amplitude and phase errors. Calibration and optimization in an active phased array system steer antenna beam to the desired direction and they are applicable in radar communications, automobiles, communication systems, and electronic warfare.

Визначення області існування показників надійності в залежності від допустимих значень показни-ків ефективності активної фазованої антенної решітки

Визначення області існування показників надійності в залежності від допустимих значень показни-ків ефективності активної фазованої антенної решітки

Fault-tolerant active phased array antenna with neural network

A model and architecture for an active phased array antenna with a neural network control unit has been developed, which provides correction of the amplitude-phase distribution depending on the quality of work of individual array modules. The possibility of adapting the system to failures of individual modules is shown.

CFD-моделювання температурного поля корпуса-радіатора передавального модуля АФАР з повітряним охолодженням

Modern radar stations are widely used to obtain images of earth surface with high spatial resolution, to identify moving objects in the air, on sea and on the ground, and allow determining the coordinates and movement parameters accurately. Active phased antenna arrays with large number of transmitting modules are widely used as antenna systems in radar stations. The heat generated by the active microwave elements of the output amplifiers of the transmitting module, leads to an increase in their temperature and to decrease in reliability. In this regard, the task of increasing the cooling efficiency of active microwave elements of the output power amplifiers is important. The aim of this study is to assess the possibilities of air cooling of the active elements of the output power amplifier in relation to the transition from gallium arsenide to gallium nitride element base with increased heat generation. This paper presents the results of computer simulation for the temperature filed of the mounting base of the radiator casing, on which 8 heat-generating elements with a local heat release of 28 W each are installed. Cooling fins are made on the opposite base of the radiator casing. The finned surface of the radiator casing is blown by an air stream with an inlet air temperature of 40°C. The simulation was carried out for three values of the air flow rate in the interfin channels: 1, 6 and 10 m/s. It is shown that the maximum temperature of the mounting base of the radiator casing is 90.1°C and is observed at an air flow rate of 1 m/s inside the interfin channels. Increasing the air speed up to 10 m/s makes it possible to reduce the temperature at the installation site of the microwave elements down to 72.1°C. A new technical solution was proposed to further improve the efficiency of the applied cooling system and to reduce the temperature of the mounting surface of the radiator casing.

Side Lobe Suppression and Gain Retaining of Practical Space-Borne Active Phased Antenna Array With Triangular Grids

In a practical space-borne active phased antenna array (APAA), main beam scanning angle (MBSA)-dependent low side lobe level (SLL) and taper loss are the ultimate and most critical performances. At some MBSA, extremely SLL in some local space is needed. The harsh limitation on APAA taper loss further complicates the problem seriously. In this paper, the main beam scanning space (MBSS) was divided into several subspaces. Instead of applying a single set of weights regardless of the MBSA, a separate set of weights is implemented independently in each subspace. This transforms the nearly unsolvable problem into multiple solvable problems. An array-decomposition approach is proposed to further reduce the number of synthesis parameters for each subspace. The entire array is simplified as an assembly of multiple sub-arrays. Each and every sub-array shares the same set of weights. The number of synthesis parameters is therefore reduced to the order of the subarray that the synthesis is much easier to solve without sacrificing too much synthesis performance. The proposed approach has been applied to solve concerned practical problem successfully.

A novel approach of remotely calibrating the active phased array antenna using PNA

This paper presents a novel approach of remotely calibrating the active phased array antenna using Pulse Network Analyser (PNA). Phased array antennas are usually calibrated at the factory using near-field range calibration. However, when these antennas are used in the field, due to the presence of solid state components, their characteristics may change over time. Owing to these changes, the requirement arises to recalibrate the array in the field. Calibration is necessary to know the element-wise transmitting power, receiver gain, attenuation, element failures and characteristics of phase shifters. A proper calibration will ensure desired antenna pattern and system accuracy. In this work, a technique that is suitable for calibration in both transmit and receive paths of phased array antenna using far-field method, is developed. A suitable setup was established for implementing the above technique using the PNA. Remote control of the setup was done using Matlab software. Results obtained indicate the successful calibration of the system.

A novel approach of remotely calibrating the active phased array antenna using PNA

This paper presents a novel approach of remotely calibrating the active phased array antenna using Pulse Network Analyser (PNA). Phased array antennas are usually calibrated at the factory using near-field range calibration. However, when these antennas are used in the field, due to the presence of solid state components, their characteristics may change over time. Owing to these changes, the requirement arises to recalibrate the array in the field. Calibration is necessary to know the element-wise transmitting power, receiver gain, attenuation, element failures and characteristics of phase shifters. A proper calibration will ensure desired antenna pattern and system accuracy. In this work, a technique that is suitable for calibration in both transmit and receive paths of phased array antenna using far-field method, is developed. A suitable setup was established for implementing the above technique using the PNA. Remote control of the setup was done using Matlab software. Results obtained indicate the successful calibration of the system.

The Impact of a Wet <inline-formula> <tex-math notation="LaTeX">$S$ </tex-math> </inline-formula>-Band Radome on Dual-Polarized Phased-Array Radar System Performance

This paper discusses the impact of a wet flat radome on the performance of a line replaceable unit active phased-array antenna developed for a dual-polarized phased-array weather radar. Water formations, such as film and droplets, were fully characterized over flat and curved radome surfaces using an analytical model as a function of the precipitation rate. Numerical simulations and experimental results validated the proposed analytical model. An active dual-polarized phased-array of $8\times 2$ elements was used to evaluate the degradation of the cross-polarization component as well as the mismatch and the phase of scanned antenna radiation patterns for vertical and horizontal polarizations. In addition, a radome panel of an $S$ -band weather radar (WSR-88D) was characterized in the far field using a single radio-frequency probe. It is demonstrated that even at the $S$ -band, the water formation on the radome affects both copolarization and cross-polarization components, degrading the overall performance of the dual-polarized radar system under rain conditions.

능동위상배열 안테나 고장 특성을 고려한 신뢰도 분석 방안 연구

Purpose: There is the limit of the existing methods (k of N model) applied in the reliability analysis of the active phased array antenna. In this study, we propose a new analysis methods considering the failure characteristics.BR Methods: In this study, the fault characteristics of the active phased array antenna are defined and the cases are summarized. And that simulate failure situations in all cases.BR Results: As a result of simulations, other cases of failure besides the previously defined failure cases occurred.BR Conclusion: Therefore, the new method is more accurate than the existing method to perform a reliability analysis method considering fault characteristics of active phased array antenna.

Wide scanned electronically steered conformal active phased array antenna for Ku-band SATCOM

AbstractThe paper describes the design and development of a low profile wide scanned conformal active 1 × 32 phased array antenna for Ku-band SATCOM applications. The realized antenna is diagonally polarized and covers full transmit frequency band (i.e. 13.75–14.5 GHz) of Ku band SATCOM. All the developed sub-systems of the antenna, i.e. conformal radiating array, conformal transmit module, manifold network, and beam steering unit are described. The VSWR of the antenna is better than 1.65 over the complete transmit frequency band. The antenna has the beam steering capability of ±60° in the array plane. Designed antenna is best suited for airborne applications, where antenna profile contributes considerable aero drag and RCS to the host platform.

화포탐지 레이다용 C-대역 평면형 능동위상배열 안테나 개발

This paper describes the development and measurement results of C-band planar active phase array antenna for detecting and tracking radar(weapon-locating radar). The antenna is designed with 14 sub-arrays(12 main channels and 2 sidelobe blanking channels and approximately 3,000 elements of transmit–receive channel) to generate transmit and digital receive patterns. Using a near-field measurements facility, G/N, transmit patterns, and received patterns are measured. Receive patterns are implemented with digital beamforming by signal processing. The measurement results demonstrate that antenna design specifications were fulfilled.

METHOD FOR CONSTRUCTING MULTIFUNCTIONAL L BAND ACTIVE PHASED ARRAY ANTENNAS FOR RADAR SYSTEMS

The article poses the urgent task of increasing the efficiency of functioning of active phased antenna arrays (APAA) radar stations. Particular attention is paid to the development of modern multifunctional phased L-band arrays. Contradictions in the main criteria for ship antennas are revealed, and ways to eliminate them are proposed. Based on the study of radar and classification systems for ship-based targets and on the analysis of the results, a new method for constructing L-band multifunctional APAA for these systems has been proposed. It is proposed to use a dipole-type emitter in antenna arrays, which operates in the decimeter range and the lower part of the centimeter range. It has high mechanical and electrical strength. The article presents a scheme for constructing an APAA classification system, simulation results and an example of the practical implementation of the proposed method.

Research on two-phase heat removal devices for power electronics

The development of modern power electronics (electronic modules based on metal–oxide semiconductor field-effect transistors, and insulated gate bipolar transistors, inverter modules, thyristor converters, transmitting modules of active phased array antennas, central processing units of computer equipment, etc.) is accompanied by a constant increase in the level of integration and the corresponding steady increase in the generated heat fluxes per unit volume of electronic components. It is promising to use heat pipes and thermosyphons as heat removal devices, since their equivalent thermal conductivity exceeds that of metals by orders of magnitude. The paper presents the results of an experimental study on the thermal resistance of a vertical aluminum heat pipe with isobutane, an environmental-friendly working fluid, in the heat removal conditions corresponding to the free convection of air. It is shown that the thermal resistance of the aluminum gravitational heat pipe with a threaded capillary structure is substantially lower than the thermal resistance of the aluminum thermosyphon of the same size which has a smooth surface of the body in the evaporation zone.

New method for testing of antenna phased array in X frequency range.

The results of the research of the developed fiber-optic transmission systems for analog high frequency signal are represented. On its basis, a new method to identify various structural defects in the active phased antenna arrays is elaborated.

Reliability Considerations of Spherical Phased Array Antenna for Satellites

Reliability is one of the most important aspects for any system onboard a satellite. This paper discusses different failure conditions and a fault-tolerant design of an active spherical phased array antenna (SPAA). This SPAA is having a hemispherical scan coverage for transmission of satellite imagery data at high bit rates to the ground station. Different failure conditions are identified and a criticality rank has been assigned based on their effects on the overall performance of the SPAA. Two entirely different configurations of the array are chosen to select the best one considering the failure effects. Based on these analyses, a rational margin is built such that the array can take care of even the most critical failure condition. This paper provides an insight toward the realization of a reliable phased array and thus useful for a practicing antenna engineer involved in designing antennas for the spacecrafts.

24-Channel Ku-Band Low-Loss Slotted Waveguide Power Divider

A 24-channel Ku-band power divider for active phased antenna array has been proposed and developed. The divider is built using a tree network with 1×3×2×2×2 structure, while all its elements are implemented using a finline. As a result, additional insertion loss of the manufactured specimen amounted to 1.8 dB that corresponds to the efficiency of about 66%. The measured isolation of the divider outputs amounted to no less than 16 dB for any pair of channels with the irregularity of power division between channels of no more than 0.3 dB in the working frequency range of 9–14 GHz.

편파가변 위성 방송 수신용 능동 위상 배열 안테나 개발

We herein present a study on the active phased array antenna for receiving satellite broadcasting that can electrically align its polarization to that of target transmitters in its moving condition or in the Skew angle arrangement of the broadcasting satellite receiver. Hence, we have developed an active phased array structure composed of the self-developed Vivaldi antenna and multifunction core (MFC) chip, receiving RF front end module, and control units. In particular, the new Vivaldi antenna designed in the Ku-band of 10.7–14.5 GHz to receive one desired polarization mode such as the horizontal or vertical by means of an MFC chip and other control units that can control the amplitude and phase of each antenna element. The test results verified that cross-polarization property is 20 dB or higher and the primary beam can be scanned clearly at approximately ±60°.