RU2662908C1 - Radio receiver - Google Patents

Abstract

FIELD: radio engineering and communications.SUBSTANCE: use to create elements and instruments of radio receivers. Essence of the invention is that a radio receiver comprising a substrate with at least one dielectric layer applied thereto, in the dielectric layer and the substrate, a recess is made, on the surface of the dielectric layer,with adjacent to the recess on its sides,there are performed a cathode, an anode, a radio electrode and a control electrode with no electrical contact between them, an array of carbon nanotubes is formed on the side surface of the cathode adjacent to the recess, the region with a recess is closed by a sealing plate.EFFECT: providing the possibility of increasing the amplitude of the output low-frequency signal by increasing the field emission current, improving the stability of the operation and the lifetime of the radio receiving device.10 cl, 5 dwg

Description

The invention relates to radio receivers using carbon nanotubes (CNTs). The invention can be used to create elements and devices of radio reception equipment.

The patent application US 2010144296 (A1) “Carbon Nanotubes for Wireless Communication and Radio Transmission” (IPC H04B 1/16, published June 10, 2010) describes a technical solution for implementing a demodulator of a radio receiving device consisting of a substrate, two electrodes that are connected with each other using CNTs. The disadvantage of this technical solution is the possibility of using CNTs only as a radio signal demodulator.

US Pat. No. 8717046 (B2) Nanotube Resonator Devices (IPC G01R 27/04; H03H 9/24, published May 6, 2014) describes a radio receiving device consisting of an anode and a cathode, on the surface of which a single carbon nanotube is fixed. There is no electrical contact between the cathode and the anode. For the operation of the radio receiving device, it is necessary to place the device in a vacuum volume to ensure the conditions for the flow of field emission from CNTs. The disadvantage of this technical solution is the lack of a control electrode, the presence of which allows to increase the stability of the field emission current without changing the voltage between the cathode and the anode, the change of which leads to a change in the resonant frequency of the CNT and a deterioration in the reception of the radio signal.

The closest set of essential features (prototype) of the invention is the technical solution described in US patent for invention US 8022791 (B2) "Radio frequency device comprised a vibratile carbon nanotube and a vibratile tuning electrode" (IPC H03H 9/24; H03H 9 / 46; H04B 1/16 published September 20, 2011). The invention describes a radio receiving device consisting of substrate No. 1, on the surface of which there is a cathode with a carbon nanotube, substrate No. 2, on the surface of which an anode with an oscillating electrode and a control electrode are formed, and substrate No. 3, on the surface of which substrate No. 1 and substrate No. 2 with the front side opposite to each other, and the vacuum housing, where the elements of the radio receiver are located. The disadvantages of this technical solution are: the use of a single CNT, this limits the maximum current density of the emission of this emitter, not allowing to achieve high gain and large output values of the detected low-frequency signal; the use of three substrates and an external vacuum housing in the design complicates the manufacturing process and imposes restrictions on the miniaturization of the radio receiver; the lack of a radio electrode in the design for connecting directly to the transmission line or an external antenna in order to ensure stable operation of the device in case of a weak radio signal source and the need to use radio-transparent materials in the design of the vacuum housing of the radio receiving device.

The technical problem of the invention is the development of the design of a radio receiving device using CNT arrays, ensuring that the elements of the radio receiving device are placed on one substrate, with the formation of a vacuum volume in the working area of the radio receiving device and a group of electrodes for inputting control and radio frequency signals into the vacuum volume of the device.

The technical result consists in increasing the amplitude of the output low-frequency signal by increasing the field emission current due to the use of CNT arrays, together with an increase in the stability and service life of the radio receiving device using carbon nanotubes.

To achieve the above technical result, the radio receiving device comprises a substrate with at least one dielectric layer deposited on it, a recess is made in the dielectric layer and the substrate, a cathode, anode, radio electrode and a control electrode are made on the surface of the dielectric layer adjacent to the recess on its opposite sides electrode with no electrical contact between them. An array of carbon nanotubes is formed on the side surface of the cathode adjacent to the recess; the region with the recess is closed by a sealing plate.

The radio receiving device differs from the prototype in that a recess is made in the dielectric layer and the substrate, a CNT array is formed on the side surface of the cathode adjacent to the recess, a radio electrode is present in the structure, and the region with the recess is closed by a sealing plate.

The formation of a recess in the dielectric layer and the substrate, the placement on the surface of the dielectric layer adjacent to the recess on its opposite sides: a cathode, anode, radio electrode and a control electrode, the formation of a CNT array on the side surface of the cathode adjacent to the recess, evacuation of the region with the recess by means of a sealing the plate provides the placement of the anode, cathode with an array of CNTs, a radio electrode and a control electrode in one plane, which simplifies the manufacturing process with a minimum iey device size. Thus, a radio receiving device is formed with a CNT array placed in the evacuated volume, this ensures a high density of the working emission current, the ability to work in a region with a large steepness, which allows to increase the device gain and to obtain a higher amplitude of the low-frequency signal at the output. The presence of an additional control electrode in the design allows you to control the density of the emission current to focus the electron flow and stabilize the detector’s operating mode (operating point on the emission I – V characteristic), and the radio electrode allows you to connect an external antenna to ensure the reception of a weak radio signal source or to match the input impedance with the outputs of different radio frequency devices and communication lines. The design forms of the control electrode and the radio electrode, for optimal interaction of electromagnetic fields with a CNT array, can be made in the form of several separate parts spaced on both sides (symmetrically) relative to the center line from the cathode to the anode, realizing a planar focusing-stabilizing system to obtain the desired density electron flow from CNTs.

In particular cases of the invention, the recess in the substrate is made in the form of a rectangular parallelepiped with a base area of 1 to 100 μm ² .

In particular cases of the invention, the recess in the substrate is made with a depth of 0.1 μm to 20 μm.

In particular cases of the invention, the end face of the cathode, anode, radio electrode and control electrode adjacent to the recess is made in the form of a rectangle or trapezoid.

In particular cases of the invention, the length of the carbon nanotube array is from 0.5 to 8 microns.

In particular cases of the invention, the cathode, anode, radio electrode and control electrode can be made of at least one layer of titanium and / or molybdenum, and / or gold, and / or platinum, and / or aluminum, and / or copper, and / or chromium and / or tungsten.

In particular cases of the invention, the substrate consists of at least one layer of silicon and / or silicon oxide, and / or glass, and / or glass, and / or aluminum oxide.

In particular cases of the invention, the dielectric layer is made of silicon oxide and / or aluminum oxide and / or silicon nitride with a thickness of 50 nm to 3 μm.

In particular cases of carrying out the invention, the sealing plate is made of silicon and / or silicon oxide, and / or glass, and / or glass, and / or aluminum oxide with a thickness of 0.1 mm to 1 mm.

In particular cases of the invention, the sealing plate is connected to the surface of the substrate by splicing by means of glass solder.

In special cases of the invention, the formed evacuated volume using a sealing plate creates a pressure of not more than 1 × 10 ^-3 Pa.

The combination of features characterizing the invention, allows to obtain a radio receiver with an increased value, gain and output amplitude of a low-frequency signal, with increased reliability and extended service life.

The invention is illustrated by drawings, where

in FIG. 1 is a top view of a radio receiver;

in FIG. 2 is a schematic illustration of a slice of a radio receiver along a dashed line;

in FIG. 3 - functional electrical circuit;

in FIG. 4 - an oscillogram for the case when the frequency of the carrier modulated signal does not coincide with the natural frequency of the CNT array;

in FIG. 5 is an oscillogram for the case when the frequency of the carrier modulated signal coincides with the natural frequency of the CNT array.

The radio receiving device comprises a substrate 1 with a dielectric layer 2 deposited thereon, a cathode 3, an anode 4, a radio electrode 5 and a control electrode 6, an array of carbon nanotubes 7, a sealing plate 8 (Fig. 1 and Fig. 2).

A recess is made in the substrate 1 with a dielectric layer 2 deposited on it, a cathode 3, anode 4, a radio electrode 5 and a control electrode 6 are formed on the surface of the dielectric layer 2 adjacent to the recess on its opposite sides. Between the cathode 3, anode 4, radio electrode 5 and control electrode 6 there are no electrical contacts. An array of carbon nanotubes 7 is grown on the side surface of the cathode 3 adjacent to the recess; the region with the recess is closed by a sealing plate 8.

The substrate 1 consists of at least one layer of silicon and / or silicon oxide, and / or glass, and / or glass, and / or aluminum oxide, the dielectric layer 2 is made of silicon oxide and / or aluminum oxide, and / or silicon nitride with a thickness of 50 nm to 3 μm. The recess in the substrate 1 is made in the form of a rectangular parallelepiped with a base area of 1 to 100 μm ² , a depth of 0.1 μm to 20 μm. The cathode 3, anode 4, the radio electrode 5 and the control electrode 6 can be made of at least one layer of titanium and / or molybdenum, and / or gold, and / or platinum, and / or aluminum, and / or copper, and / or chromium and / or tungsten. The ends of the cathode 3, the anode 4, the radio electrode 5 and the control electrode 6, adjacent to the recess, can be made in the form of a rectangle or trapezoid. The length of the array of carbon nanotubes 7 is from 0.5 to 8 microns. The sealing plate 8 may be made of silicon and / or silicon oxide, and / or glass, and / or glass, and / or aluminum oxide with a thickness of 0.1 mm to 1 mm and is connected to the surface of the substrate 1 by splicing by means of glass solder 9 . In the formed evacuated volume using a sealing plate 8 creates a pressure of not more than 1 × 10 ^-3 Pa.

The radio device operates as follows.

When a modulated radio signal is supplied if the carrier frequency of the radio signal coincides with the natural oscillation frequency of the CNT 7 array in the anode 4 circuit, in addition to the constant emission current, an alternating current will arise in the circuit due to the forced oscillations of the CNT, while the amplitude of this current will sharply increase during resonance. Due to the nonlinear characteristics of the working element (emission cell from CNTs), the instantaneous value of this current in the low-frequency region will obey the law of modulation of the received (detected) radio signal, in particular for amplitude modulation (AM), the value of the low-frequency alternating current will repeat the envelope of the AM signal. In the article (Barkaline V., Abramov I., Belogurov E., Chashynski A. Simulation of Carbon Nanotubes and Resonant Excitation of their Mechanical Vibrations by Electromagnetic Field for Nanoradio // Applications Nonlinear Phenomena in Complex Systems. 2012. Vol. 15, no 1. PP. 23-42.) Based on theoretical calculations, the possibility of exciting the CNT array as a whole is shown, which confirms the possibility of using the CNT array as an active element when creating a radio receiving device using CNTs. To verify the operability of a radio receiving device using CNTs, one can use the functional diagram shown in FIG. 3. To demonstrate the operation of the radio receiver, a constant voltage source E1, a constant current meter PA1, a voltage source with E2 control and a differential amplifier DA1 are required. Resistors in the circuit of the anode R1 and the control electrode R2 are necessary to limit the maximum current flowing through the device. Their exclusion from the scheme is also allowed.

To generate a radio signal, it is proposed to use an RF generator with modulation to transmit a test signal with an information component directly to an array of CNTs 7 or a radio electrode 5 connected to the antenna through a radiating antenna. It is proposed to use an oscilloscope or other recording (processing, analyzing) information signal device as a recording device.

To register the information signal, it is proposed to include a resistor R3 in the circuit of the anode 4, the alternating voltage measured on it will be proportional to the flowing emission current resulting from the detection. Capacitors C1 and C2 are necessary to block the ingress of direct voltage to the amplifier input. A two-channel source meter with a low noise level was used as a power system for a radio receiving device. Such a device allows you to simultaneously set and control the operating voltage of the device, stabilize its operating current using a feedback channel. The differential amplifier must provide the necessary bandwidth for the information signal and gain for the finished recording device, such as an oscilloscope.

To ensure the correct operation of the device, the source-meter is sufficient to use in the mode of the voltage source. The first channel of this device is connected to the anode 4. The second channel is connected to the control electrode 6. The cathode 3 is common to both sources. The required voltage at the anode 4 is set by a constant voltage source E1, and the current (I _A ) in the circuit of the anode 4 is measured by an ammeter PA1. The value of this voltage is selected in such a way as to obtain a stable emission current (I _E ), the value of this current is controlled by PA1. The voltage value (V _U ) at the control electrode 6 is set by the second voltage source E2 and subsequently, it is automatically adjusted during the operation of the radio receiving device so that the direct current flowing through the resistor R3 in the anode 4 circuit has a fixed value equal to the emission emission current set at the beginning, I _A → IE ₀ . As an adjustment algorithm, it is proposed to use the following formula:

where β is the feedback coefficient that determines the depth and range of adjustment of the operating current for the device. In practice, when the device is operating, the source E2 must provide a voltage substring V _{U in} proportion to the current difference I _A -I _E0 , where the current I _A is measured by PA1. This stabilization of the operating current is necessary to compensate for the instability of the emission current from the CNT 7 array. For the stabilization to function correctly, certain restrictions on the speed of operation are imposed on the feedback between the E2 source and the PA2 meter. The feedback time constant should not be very large, otherwise fast fluctuations of the emission current will not be monitored, on the other hand, it should not be less in time than the slowest (lowest private) processes in the information signal.

Example

A carbon nanotube receiving device contains a silicon substrate with 2 μm thick silicon oxide deposited on its surface, a recess in the form of a rectangular parallelepiped with sides of the base 5 μm to 5 μm deep 4 μm deep, on the surface of the dielectric layer adjacent to the recess on its opposite sides, a cathode, anode, radio electrode and a control electrode of titanium with a thickness of 500 nm are made, the ends of which are made in the form of a rectangle 4 μm wide, An array of carbon nanotubes up to 4 μm long is grown on the side surface of the cathode adjacent to the recess; the region with the recess is closed by a silicon sealing plate by splicing the substrate and the plate using a 50 mm thick glass solder layer at a pressure of no higher than 5 × 10 ^-4 Pa.

In FIG. Figure 4 shows a working oscillogram for the case when the frequency of the carrier modulated signal does not coincide with the natural frequency of the CNT array. The gray color shows the AM modulated RF signal, for control measured from the output of the test generator. Black color shows the output signal of the device corresponding to an alternating current in the anode circuit, having a noise character, due to leakage field emission from CNTs. In FIG. Figure 5 shows a working oscillogram for another case when the carrier frequency of the transmitted modulated signal coincides with the natural frequency of the CNT array. The AM modulated RF signal is shown in gray, for measurement it is measured at the generator output, and the real-time detection signal corresponding to the alternating current in the anode circuit is shown in black. If the carrier frequency of the radio signal coincides with the resonant frequency of the CNT array, a strong and distinguishable current will appear in the anode circuit, corresponding to the envelope of the RF signal, and the signal will be detected, as shown in the oscillogram (Fig. 5).

Claims (10)

1. A radio receiving device containing a substrate with at least one dielectric layer deposited on it, a recess is made in the dielectric layer and the substrate, a cathode, anode, radio electrode and a control electrode are made on the sides of the dielectric layer adjacent to the recess, with no electrical contact between them, on the side surface of the cathode adjacent to the recess, an array of carbon nanotubes is formed, the region with the recess is closed by a sealing plate. 2. The radio receiving device according to claim 1, characterized in that the recess in the substrate is made in the form of a rectangular parallelepiped with a base area of 1 to 100 μm ² . 3. The radio receiving device according to claim 1, characterized in that the recess in the substrate is made from a depth of 0.1 μm to 20 μm. 4. The radio receiving device according to claim 1, characterized in that the end face of the cathode, anode, radio electrode and control electrode adjacent to the recess is made in the form of a rectangle or trapezoid. 5. The radio receiver according to claim 1, characterized in that the length of the carbon nanotube array is from 0.5 to 8 microns. 6. The radio receiving device according to claim 1, characterized in that the cathode, anode, radio electrode and control electrode can be made of at least one layer of titanium and / or molybdenum, and / or gold, and / or platinum, and / or aluminum and / or copper and / or chromium and / or tungsten. 7. The radio receiver according to claim 1, characterized in that the substrate consists of at least one layer of silicon and / or silicon oxide, and / or glass, and / or glass, and / or aluminum oxide. 8. The radio receiving device according to claim 1, characterized in that the dielectric layer is made of silicon oxide and / or aluminum oxide and / or silicon nitride with a thickness of 50 nm to 3 μm. 9. The radio receiving device according to claim 1, characterized in that the sealing plate is made of silicon and / or silicon oxide, and / or glass, and / or glass, and / or aluminum oxide with a thickness of 0.1 mm to 1 mm. 10. The radio receiving device according to claim 1, characterized in that the sealing plate is connected to the surface of the substrate by splicing by means of glass solder with the formation in the region of the deepening vacuum with a pressure of not more than 1 × 10 ^-3 Pa.

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