A Knowledge Reuse–Based Approach for Rapid Design of an Active Phased Array Antenna

The basic principles of building a promising domestic regional satellite communication system "Express-RV", based on the highly elliptical orbit "Molniya" and intended for broadband access of civil sector subscribers to various public communication networks, in particular to the Internet, are considered. The main technical requirements for the antenna systems of mobile satellite communication terminals of the Express-RV system are formulated. The necessity of using active phased array antennas for a number of types of such terminals is justified. A brief overview of the principles of implementation and examples of the design of microstrip active phased array antennas, including their elementary emitters and individual modules, are given. The problem of the occurrence of the blinding effect inherent in flat microstrip gratings made on dielectric substrates is noted; measures to compensate for this effect are considered. The possibility of expanding the maximum scanning angle of a narrowly directed beam of an active phased array antenna by using a magnetically controlled scattering dielectric lens, as well as creating segment-dome structures of antenna systems in relation to mobile terminals of mobile satellite communications of the "Express-RV" system, is shown. Simple analytical relations are derived that allow us to estimate the number of elementary emitters required for the implementation of a receiving-transmitting active phased array antenna with specified technical characteristics: gain and maximum scanning angle; the corresponding dependencies are given. The cost of creating an antenna system based on an active phased array is estimated.

With the further development of space communication satellite payload technology, the demand for active phased array antenna (APAA) is increasing, and heat dissipation is a key technical problem affecting the performance of APAA. In order to ensure an ideal temperature range and reduce temperature difference in orbit, a thermal design method of a high power APAA of GEO communication satellite is proposed. The heat pipes are embedded in the active satellite installing plate to solve the heat collection, uniformly distributing temperature and heat transfer, and the active satellite installing plate is not only the structural support of the antenna but also the cooling plate of the antenna. The heat of APAA is taken away by integrated thermal coupling with the satellite platform, which is exchanged between both sides of the active satellite installing plate and the cold plate based liquid cooling, and afterwards is transmitted to the thermal radiators of satellite through single-phased fluid loop. The simulation analysis results show that the temperature and the temperature difference of the APAA meet the requirements of thermal reliability and design performance. The thermal control method used provides a feasible design reference for the thermal design of similar GEO orbit communication satellite APAA.KeywordsThermal designGEO communication satelliteActive phased array antenna (APAA)Structure and thermal control integrationIntegrated thermal couplingActive satellite installing plateHeat pipeCold plate based liquid cooling

The purpose of this article is to review and justify the choice of emitters for constructing energy-efficient high-performance broadband active phased L-band antenna array with wide-angle scanning in 2 planes. Phased antenna array characteristics, accepted as reference: wide scan angle in the H-plane  not less than ± 450; a wide range of frequencies  at least 40%; small overall dimensions of the radiating aperture, not allowing to consider the canvas without taking into account edge effects; high energy potential, which means high electric strength (up to 1 kW per channel); reduced spurious emission outside the scanning area (more than 45 °). Here are the requirements for the emitters of the above-described active phased antenna array: Emitters dimensions must comply with the structural requirements for the antenna array construction (array step, emitters arrangement method) and not «obscure» each other in the area of the working scanning angles in the E and H plane. Emitters spatial bottom width in the grating should not be less than the angular width of the area of electronic scanning of the active phased antenna array beam. Beam main lobe distortion in the scanning area by an amount higher than 1 dB is not allowed. The emitter in the grating should be consistent with the power system in the working range of scanning angles and frequencies. Reduced spurious emission in directions outside the scanning area. High efficiency, to ensure both reception and transmission, and sufficient dielectric strength with limited dimensions. As active phased antenna array emitters, the simplest weakly directional antennas are used, which is associated with their low cost and high manufacturability. Technical solutions in the class of vibrator antennas (dipoles) are subjected to further analysis. The use of dipole antenna arrays in wide-angle and broadband applications leads to a number of technical limitations, such as: limited broadband emitters (including and as part of the antenna array), determined by their design features and mutual influence; a limited sector of the formation of unidirectional radiation (shape stability (radiation pattern) in the frequency band, determined by the condition for the appearance of interference lobes and the mutual influence of the emitters, leading to distortion of the amplitude-phase distribution; the occurrence of the effect of «blinding» of the lattice in individual sectors of the scan and frequencies associated with the effects of external (spatial) and internal interaction of emitters. Based on the above requirements for emitters, taking into account the design features of the AFAR, the following most important technical problems can be identified, the solution of which must be considered: ensuring a wide working frequency band; ensuring consistency in a wide sector of scanning angles; ensuring a stable spatial pattern of the emitter in the grating. Consider the general constructive methods that can be used to solve the above problems. Group them according to the constituent structural elements of the vibrator: Shoulders shape of the vibrators. The main limitation of the classical symmetric vibrator emitter using is its small working frequency band (up to 10%). So the passband ( 2f ) of a symmetric half-wave vibrator can be estimated by the following expression [5, p. 187]: 4 73,1 2 f f0 ,  WВ where is WВ  the wave impedance of the vibrator. It is determined by the cross section, shape and length of the shoulders. Balancing device type. Using a coaxial line determines the presence of balancing devices to power the shoulders of the vibrators. In the decimeter range, various types of balancing devices are used, the basis of which are various loops (including the U-elbow), glasses, transformers and slots, as well as their combinations. 3. Reflector shape (including matching structural elements). In fixed sector vibrator headlamps, a solid conductive surface is usually used as a reflector. Its shape and location relative to the shoulders has a strong effect on the bottom of the emitter in the grating and the matching of the grating in wide scanning angles and in the frequency range. The factor taking into account the influence of a flat aperiodic reflector on the DN is estimated by the expression: Fра  sin(kdr cos ) , where is dr  the distance from the vibrator to the reflector.

The present paper discusses design and developmental aspects of active phased array antennas (APAs). It focusses on technological aspects involved in the design for achieving wide bandwidth and wide scanning APAs. The paper compares dense and sparse APAs with the aid of few case studies supported with measurements.

This paper presents the conceptual design of system with APAA (active phased array antenna) for HAPS in Ka band. Ka band transmitter and receiver will be designed using the system developed in S band. Characteristics of one element for multibeam antenna is simulated, fabricated, and tested. Also, in this paper, radiation pattern of APAA with 19 elements based on the simulation values and experimental results of one element are compared.

In active phased-array antennas, the transmit and receive functions are distributed at the antenna aperture using transmit and receive (T/R) modules. The use of T/R modules provides a significant improvement in antenna performance and flexibility in the choice of array architectures. We present a review of various beamformer architectures for active phased-array antennas. This review is limited to corporate-fed active phased-array antennas for radar applications. Beamformer architectures for narrow and wide bandwidth arrays, including the choice of applying an amplitude taper in the T/R module or beamformer network are discussed. Beamformer architectures that increase antenna reliability are also presented.

Design method and key technologies of a Ku band low profile Active Phased Array Antenna (APAA) with polarization tracking for satcom on the move (SOTM) system are given. The approach presented here realizes polarization tracking and wide-angle beam tracking simultaneously comparing with traditional antennas. To be adequate for wide-angle beam scanning, the microstrip patch array antennas are presented. The choke groove is also adopted to improve the isolation between the transmitting and receiving antenna under the condition of limited size. Finally, a low profile active phased array antenna has been developed successfully. The test result shows arbitrary linear polarization and wide-angle beam tracking can be obtained from different phase setting. There is enough isolation between transmitting and receiving antennas to ensure that the performance of receiving antenna will not deteriorate.

In order to realize wide-band and low side-lobe of both E- and H-plane scanning Active Phased Array Antenna (APAA) for Ka-band, a 8*8 micro-strip patch APAA with 0.5 wavelength element spacing is analyzed in this paper. The passive patches in the rim of the antenna array can greatly decrease the side-lobe of 6 dB. The APAA of 1*8 elements with +/-40 degree scanning were designed, measured and analyzed.

High data rate satellite communication system called Gigabit Satellite, which can achieve the transmission rate of more than 1.2 Gbps, is planned to launch as an experimental satellite in Japan and the basic consideration for this program has been proceeded. In this system, a Kaband scanning spot beam antenna (SSBA) with multiple beams is required. Therefore, an active phased array antenna (APAA) which can steer the multiple beam electrically is considered and one can realize high EIRP and G/T performance for multiple international service areas. An APAA realizes flexible multiple beam forming by using a beam forming network (BFN) with phase shifter. Since the performance such as antenna gain and beam scanning properties are restricted by the antenna configuration, we have been studying the feasibility of the Ka-band APAA. APAA has been developed mainly for radar systems for many years. CRL and MELCO have been developed the S-band APAA for intersatellite communication of the engineering test satellite launched in 1994. As the Gigabit satellite, CRL and MELCO are investigating and developing the direct radiating APAA for communication satellites which can operate under wide frequency band in Ka-band. This paper describes the preliminary study results of the Ka-band APAA for Gigabit Satellite.

A generalized probabilistic-physical model of reliability of a two-level active phased antenna array (APAA) of a multifunctional radar station was presented.When constructing the APAA physical model, definitions of failures of the radiating channel and the antenna array as a whole were formulated. Key parameters of the APAA were chosen: radiation power, gain in transmission and the top level of the near side lobes. This has made it possible to formulate generalized criteria of failure of the APAA operating in the modes of transmission and reception as well as determine the permissible number of failures of the radiating channels and receiving modules. The physical model of the APAA reliability was formalized by a system of equations describing deviation of key parameters of the antenna array beyond the permissible limits. At the same time, boundary (permissible) values of the number of failed radiating channels and receiving modules were found that provide critical (minimum permissible) values of key parameters of the antenna array.To construct a probabilistic model of the APAA reliability, the antenna array was defined as an isotropic hierarchical system and a formula was derived for determining the average number of operable radiating channels in the multi-level APAA structure. A block-diagram of reliability of receiving and transmitting sub-arrays, receiving and transmitting APAA has been built and formalized. Definition of failures of the receiving and transmitting sub-arrays, receiving and transmitting APAA was given. This has allowed us to derive analytical expressions for determining mean time to failure, probability of failure-free operation, density of time to failure and failure rates for sub-arrays and the APAA. Exponential distribution (for sudden failures), diffusional non-monotonic distribution (for gradual failures) and composition of exponential and diffusional non-monotonic distributions (at a joint manifestation of sudden and gradual failures) were used as models of failure of SHF elements, transistors, radiating channels and receiving modules. An illustrative example of calculation of the average time to failure of a two-level APAA of a multifunctional RS including 6400 radiating channels was presented.

[Abstract] Phased array antenna (PAA) has attracted attention for use as a hopping spot beam antenna that can potentially be used as an electronically controllable onboard satellite antenna. In fact, Japan Aerospace Exploration Agency (JAXA) has developed a Ka band active phased array antenna (APAA) installed on the Wideband Internetworking engineering test and Demonstration Satellite (WINDS). We developed flight models of the APAA and verified its performance, including its radiation characteristics. This paper describes the design of the APAA and development results of the flight model. I. Introduction PAA has attracted attention for use as a hopping spot beam antenna that can potentially be used as an electronically controllable onboard satellite antenna. In fact, a Ka band APAA will be installed on the WINDS. WINDS has been developed to construct a high-speed satellite communication system and demonstrate the advanced technology that is necessary for the formation of the satellite commnications network. The system aims at maximum speed of 155 Mbps / 6 Mbps for households with a 45-centimeter aperture antenna, which is the same size as existing communications satellite antenna, and ultra-high speed of 1.2 Gbps communication for offices with a five-meter diameter antenna. In addition to establishing a domestic ultra high speed Internet network, the project also aims to realize ultra-high speed international Internet access, especially with Asian Pacific countries and regions. WINDS project is under joint development by JAXA and National Institute of Information and Communications Technology (NICT). WINDS will be launched by an H-IIA Launch Vehicle in early 2008. The APAA is composed of a transmitting antenna and a receiving antenna, and each antenna has two hopping spot beams. The direction of each beam can be controlled independently, flexibly and rapidly. These beams can also realize the satellite switched time division multiple access (SS-TDMA) communication functions. The hopping spot beam function and SS-TDMA communication systems will be utilized for broadband communication experiments covering the Asia-Pacific region. The key features of the APAA are the minimal number of elements, development of RF components operating over 1.1 GHz bandwidth, monolithic microwave integrated circuit (MMIC) devices, and high density packages for miniaturization and lightness. This paper describes the WINDS APAA configuration, and development results of the flight model.

The active phased array antenna is a direction of modern radar development. But it is expensive. So the key in meteorological radar design is to get high ratio of capability and cost. We used 400 cross-polarization half wave diploes as radiation unit to get a high efficiency and reliability antenna, it also has low side lobe by Taylor weighting. 20 transmit/receive(T/R) modules produced too little heat to disperse, so it can be cooled by nature wind. 40 power dividers which one is divided into twenty parts and 1 power combiner decreased transmission loss. This antenna is fit for the need of wind profiling radar.

In this study, we demonstrate the results of a 64-array active phased antenna for radar wind profiler. The main part, the active phased array antenna, had the form of a bent dipole antenna with improved isolation from the adjacent antenna. Based on the system parameter analysis, 64 transmit/receive modules(TRMs) were designed. In particular, the TRMs have the function of phase/attenuation control, which plays a key role in the active phased array antenna. Measurement results of the 64-array active phased antenna, with a 20° beam steering angle with electronic control, showed the proper antenna gain, good beamwidth characteristics, and excellent radiation characteristics without distortion. These results indicate that the active phased array antenna can be applied to radar wind profilers

This paper describes the receiver design of active phased array antenna (APAA) for mobile broadcasting and communications service via satellite. This system was optimally designed with RX-channels on the consideration of minimum size and cost besides electric performances. A dual-band and dual-polarized microstrip 8 × 4 array antenna was designed as a radiator. This antenna had high directivity and wide impedance bandwidth with dual-feeding structures such as the microstrip direct feeding for Band1 and the aperture coupled strip-line feeding structure for Band2. For system minimization, active channel blocks (ACBs) playing the role for signal amplification and phase control were directly combined behind the radiators with band pass filters (BPF). A beam-forming module was designed by 10:4 channel combining structure. Thus, the satellite signal power received from 10 radiators was combined into 4 channels for satellite auto tracking and signal demodulation on vehicles. Finally, to confirm the normal operations of the system, the outdoor communications test in a satellite communication environment was accomplished by the main terminal that provided satellite Internet service.

Multichannel microwave components are widely used and the active phased array antenna is a typical representative. The high power generated from T/R modules in active phased array antenna (APAA) leads to the degradation of its electrical performances, which seriously restricts the development of high-performance APAA. Therefore, to meet the demand of thermal design for APAA, a multiobjective optimization design model of cold plate is proposed. Furthermore, in order to achieve temperature uniformity and case temperature restrictions of APAA simultaneously, optimization model of channel structure is developed. Besides, an airborne active phased array antenna was tested as an example to verify the validity of the optimization model. The valuable results provide important reference for engineers to enhance thermal design technology of antennas.