Receiving and transmitting modules of onboard radar systems
JSC “SPE “Radiy” has considerable experience in the development and production of electronic component base and radio electronic devices and systems based on them. Currently, the company develops and manufactures microwave units and modules for various purposes, microwave multi-channel receivers of onboard radar systems.
Multifunctional blocks of the microwave range are used as microwave receivers and analog-to-digital signal converters.
The line of microwave products is represented by the following blocks:
The THREE-CHANNEL RECEIVING UNIT with double frequency conversion is intended for use as a microwave receiver of onboard radars.
The THREE-CHANNEL ANALOG-TO-DIGITAL SIGNAL CONVERSION UNIT is designed for analog-to-digital signal conversion of the receiving unit for communication with the onboard programmable processor.
The LOW-NOISE TRANSISTOR MICROWAVE AMPLIFIER MODULE is designed to be used as an input stage of a radar receiver.
Vacuum microelectronics based on auto-emission cathodes
One of the promising areas of development of the element base for new generation devices is vacuum microelectronics (VME), a technology for creating electronic components characterized by micrometer geometric dimensions in which the movement of electrons occurs in a technical vacuum, unlike solid–state electronics, where electrons are localized inside the crystal lattice.
VME devices will have ultra-high performance, high resistance to radiation, low sensitivity to temperature and high efficiency. These characteristics are necessary for devices operating in conditions of high radiation and temperature. Particularly promising is the use of these devices to create a new generation of cellular and satellite telephone systems, radar stations and ultrafast computers. The development of the vacuum microelectronics industry can become an important stage in the technological development of the country and give Russia one of the points of industrial, scientific and military superiority.
There are three key stages in the development of VME:
Development and creation of auto-emission “cold” cathodes (CC), the functioning of which is based on the “pulling out” of electrons from a metal (or semiconductor) and injecting them into a vacuum in sufficient quantity and with a small energy spread for subsequent use in the device being designed.
Development and creation of the structure of the basic devices (BD) of the VME of the required dimensions and tolerances, including the application of thin layers of materials and dielectrics with such physical properties as are suitable for devices.
Development and creation of a line of devices based on the BD VME.
A significant advantage of the development of the VME direction as the basis of a new generation of electronic devices is the scientific and technical reserve created in our country. This is, first of all, the scientific and technical potential accumulated over the previous years in the field of the development of lamp devices on thermonacal cathodes, which provides a rich base for the modernization of these devices based on the use of highly efficient new type of autoelectronic emitters.
For a number of years, JSC “SPE “Radiy” has been conducting proactive research and development work aimed at developing technologies and creating prototypes of CC and BD VME. The company has carried out a large amount of research on the first stage and successfully completed it, as well as made a serious start on the second stage.
Stage 1 works
Today, JSC “SPE “Radiy” has a key technology for creating the main element of the VME BD – auto-emission CC, the characteristics of which are many times higher than all world analogues. The company, at its own expense, has developed and created a unique “RUNA” installation, which has developed a technology for creating long-lived auto-emission “cold” cathodes (CC) with preliminary “seeding” of substrates on the ARDIS-100 installation. The appearance of these installations is shown in Fig.1.
Cathodes are formed by plasma gas-phase deposition (CVD) of nanocrystalline graphite (NCG) on substrates up to 100 mm in diameter. Materials such as silicon, molybdenum, titanium and glass carbon are used as substrates. The process of CC formation in the plasma of the RUNA installation is demonstrated in Fig. 2.
The installation makes it possible to obtain large-sized CC with a uniform distribution of emission centers over the entire surface, as well as cathodes with selective emission centers of arbitrary shape and size. The synthesized material has high adhesion, chemical resistance and mechanical strength, which makes it possible to work with it under normal conditions of traditional vacuum electronics. Figure 3 shows the structure of the emission film in an electron microscope, and Figure 4 shows photographs of the obtained substrates with an emission film.
Fig. 3. The structure of the emission film in an electron microscope
Various diagnostic stands have been developed and installed at the enterprise for testing cathodes and products based on them. Figure 5 below shows one of them – the EN-101 stand.
Fig. 5. Stand EN-101
Cold cathodes developed at JSC “SPE “Radiy” have high specific characteristics and a large working resource – current densities above 10 A / cm2, a resource above 700 hours at a constant current of 1 A / cm2. To date, such characteristics of cold cathodes have not been demonstrated in the world literature. The uniqueness of the characteristics of CC based on NCG is confirmed by numerous tests conducted at the enterprise, as well as by leading American laboratories. This is precisely the competitive advantage that will allow Russia to open a new era of miniature vacuum electronic devices and vacuum integrated circuits with autoelectronic emission.
Stage 2 works
During the implementation of the second stage, miniature controlled electron sources (CES) for small-sized vacuum devices and thin-film structures on silicon – cathode-grid (KGN) and anode-grid nodes (AGN) were developed, necessary for the creation of BD VME -vacuum microtriodes (VMT). The main task of the stage was the development and creation of prototypes of the VMT. However, vacuum microtriodes, even of the simplest kind, have a complex geometry, and to describe the processes occurring in them, it is necessary to take into account many physical phenomena. Since the construction of a complete microtriode model is a very difficult task, it was necessary to first gain experience in creating prefabricated CES structures. As such a product, the company has developed and created a miniature electronic gun in the form of a CES, the design of which is shown in Fig. 6.
Fig.6. The design of a miniature CES
The molybdenum cathode, made in the form of a “fungus”, was covered with an auto-emission film at the RUNA installation. Figure 7 shows a photo of such cathodes.
Fig.7. Example of cathodes for a miniature CES
The diameter of the molybdenum cathode is 2.5 mm, the height is 3 mm. All the cathodes received passed the emission test. An example of the structure of the emission film and its emission image on the phosphor of one of the cathodes are shown below in Fig.8.
One of the main and responsible nodes of the CES is the grid, which provides field emission – the “pulling out” of electrons from the CC. Unfortunately, the quality of mass-produced metal grids does not allow the miniaturization of cathode-grid nodes based on auto-emission cathodes. Therefore, it was decided to develop and manufacture silicon mesh nodes by lithography. During the development of silicon grid nodes, mathematical modeling of the distribution of thermal loads on the grid strings was carried out with their different configurations and different dissipated power of the UIE. 9 shows the results of calculations indicating the possibility of creating silicon grid nodes with the necessary parameters.
Fig.9. Calculation of the temperature of the silicon mesh strings
Based on the simulation results, a technology for the production of silicon grids was developed, mesh nodes of various configurations were manufactured and tested. A silicon mesh with rectangular cells and unloading beams was used as a grid node for the created CES (Fig. 10).
Fig.10. Silicon grid node with rectangular cells for CES
Figures 11 and 12 below show silicon mesh nodes of the “honeycomb” type and nodes with a dynamic coefficient of thermal expansion of the “spiral” type.
Fig.11. Silicon mesh node of the “honeycomb” type
Fig.12. Silicon mesh node of the “spiral” type
Fig.13 shows the appearance of the prototype CES and its current-voltage characteristic.
Fig.13. The appearance of the manufactured CES and its voltage characteristic
In the future, the research results obtained during the development of prefabricated structures of the CES allowed us to proceed with the main task of the project – the creation of a VMT, as a BD VME. The technology of manufacturing of the prototype VMT was reduced to the development of the processes of manufacturing monolithic KGN and AGN by silicon submicron micromechanics. The models of the VMT were developed as vacuum-solid-state KGN and AGN based on single-crystal silicon wafers. The diagram of one cell of the VMT layout and a photo of a separate cell of the KGN is shown in Fig.14
Fig. 14. Diagram of one cell of the VMT layout (left) and a photo of a separate KGN cell made in a silicon wafer by submicron micromechanics. 1- cold cathode; 2 –pulling electrode; 3 – insulator; 4 – silicon substrate; 5 – anode collector
The cells can be controlled individually with the help of appropriate metal electrodes or combined into groups – arrays. All operations were initially tested on test plates – “satellites”, taking into account the qualitative assessment of the lithography process and mathematical modeling of the electron trajectory for various geometric and electrical parameters of the KGN . Fig.15 illustrates the results of calculating the distribution of the electric field in the KGN cell, which determines the trajectories of electrons “torn” from the CC.
Fig.15. Distribution of the pulling field in the KGN and electron trajectories
In the process of obtaining arrays of KGN or AGN based on single-crystal silicon wafers, studies were conducted to verify the suitability and optimization of materials selected during their production, as well as experiments on the deposition of an auto-emission film on such structures. 16 shows a photo of the resulting sample with an array of KGN cells on a silicon wafer and an example of a deposited emission film on such a sample.
Fig.16. Photos of arrays of KGN cells on a silicon wafer. On the left is clean, on the right – with a precipitated emission film
During the experiments, the deposition technology of the auto-emission film was optimized. As a result, it was possible to achieve an acceptable quality of manufacturing of an array of KGN and AGN cells, with a selectively deposited emission film.
To demonstrate the possibility of implementing a basic VME device, a mock-up of a prototype of a VMT was implemented. A characteristic view of the voltammeric characteristic (VAC) of the prototype model of the VMT is shown in Fig. 17.
It is important that the control range of such a device is below 100 volts, which is attractive for creating microelectronic devices.
According to the results of these studies, JSC “SPE “Radiy” has issued 10 patents
List of patents of JSC “SPE “Radiy” in the direction of BD VMT:
1) Diode assembly for microwave protective devices – RU Patent for invention (2014) No. 2535915
2) Restrictive element for microwave protective devices – RU Patent for utility model (2014) No. 138411
3)Diode assembly for microwave protective devices – RU Patent for invention (2014) No. 2535915
4) Electrode Assembly of Electronic Devices – RU Patent for invention (2015) No. 2551350
5) A controlled emitting unit of electronic devices with autoelectronic emission and an X-ray tube with such an emitting unit – RU Patent for invention (2016) No. 2581835
6) An electron source with an autoelectronic emitter and an X-ray tube with such an electron source – RU Patent for invention (2016) No. 2581833
7) Electron source with autoelectronic emitters – RU Patent for invention (2016) No. 2586628
8) A method for manufacturing a cathode-grid assembly of an electronic device with autoelectronic emission – RU Patent for invention (2018) No. 2653531
9) Method of modification of the emission surface of electrodes for devices with autoelectronic emission – RU Patent for invention (2018) No. 2652980
10) A method for manufacturing a cathode-grid assembly of an electronic device with cold emission – RU Patent for invention (2018) No. 2652981
Electron-optical systems based on auto-emission cathodes
The analysis of the current state of this sphere and the development of new technologies is carried out.
Aerogels based on graphene and carbon nanotubes
The aerogel created at the enterprise based on a composite of graphene and carbon nanotubes (RF Patent No. 2662484 Method for producing an electrically conductive hydrophilic aerogel based on a composite of graphene and carbon nanotubes) can be considered as a matrix for storing hydrogen. In the photo, the appearance and structure of the aerogel.
The method for producing aerogel based on a composite of graphene and carbon nanotubes relates to the chemical, electrical industry, environmental protection and nanotechnology and can be used in the manufacture of elastic and flexible conductors, electrically conductive polymer composite materials, sorbents, vibration damping materials, batteries and ultra-capacitors. At the first stage, colloidal graphene oxide is obtained, for which the powder of intermediate product 1 is first obtained by acid treatment of graphite flakes, filtration, washing, drying and high-temperature treatment of the precipitate for no more than 10 minutes by microwave radiation in a microwave oven with a volumetric radiation density of no more than 0.1 W / cm3. Then the powder of the intermediate product 2 is obtained by treating the intermediate product 1 with sulfuric acid, potassium persulfate and phosphoric anhydride, cooling, filtration, washing and drying of the precipitate. The resulting intermediate product 2 is treated with concentrated sulfuric acid at a reduced temperature. Potassium permanganate is added to the resulting suspension, the temperature is raised to room temperature, hydrogen peroxide is introduced. The resulting colloidal solution is washed, filtered or centrifuged. At the second stage, a hybrid hydrogel based on a composite of graphene and carbon nanotubes is obtained by mixing colloidal solutions of graphene oxide and carbon nanotubes in a volume ratio of at least 12:1, adding an organic reducing agent – D-glucose and heat treatment of the resulting final mixture. At the third stage, the hybrid hydrogel is freeze-dried to produce an aerogel based on a composite of graphene and carbon nanotubes. The resulting aerogel is additionally treated with microwave radiation in a microwave oven. After the third stage, an additional stage of hydrophilization of the resulting aerogel is carried out, treating it with a boiling mixed dilute solution containing 3-9% nitric acid and 0.5-1.5% hydrogen peroxide, at a ratio of T: W from 1: 70 to 1:50 for 10-20 minutes. The resulting aerogel, along with electrical conductivity, has hydrophilicity, has a narrow pore size distribution and is obtained in a safe way.