CN1652400A - Voltage control adaptive aerial - Google Patents

Abstract

The invention discloses an adaptive antenna for mobile communication. The voltage control adaptive antenna is composed of N antenna array elements and a radio wave beam reflector 10, 10 is arranged on the side of the antenna array element, and the antenna array element is composed of a director 1, a variable dielectric layer 2, and a first antenna oscillator 3 , a second antenna vibrator 4, an upper electrode 5, a lower electrode 6 and an adjustable DC power supply 7, 3 and 4 are fixed on the side surface of 2 facing 10, 1 is fixed on the side surface of 2 facing away from 10, 5 is fixed on the top of 2, 6 is fixed on the bottom of 2, and the two output terminals of 7 are respectively connected to 5 and 6, and the piezoelectric constant in the direction of 5 and 6 in 2 is greater than that perpendicular to the direction of their connection. 7. Apply an electric field to 2 to change the dielectric constant of 2, so that the phase characteristics of the electric wave passing through the medium change, and finally change the direction of the synthesized beam. Delay control no longer requires data storage, and the control is very easy to implement.

Description

Voltage Controlled Adaptive Antenna

Technical field:

The invention relates to an adaptive antenna for mobile communication.

Background technique:

Ordinary directional antennas cannot automatically change direction according to needs. In order to adapt to the requirements of factors such as user movement, ordinary directional antennas change the lobes of the antenna by adjusting the thickness of the dielectric layer and the distance between the antenna oscillator and the metal reflector, which is very troublesome. The electrically tuned directional antenna uses signal phase (delay) adjustment to strengthen or suppress signals in a specific direction. Its basic structure is shown in Figure 1. The current smart antenna uses multiple same array elements, and controls the composite phase of the signal by adjusting the phase (delay) of antenna signals of different array elements, as shown in Figure 2, by changing the delay in different line array elements The specific delay value can be used to obtain radio wave beams with different phases, so that the signals at different spatial positions can strengthen or cancel each other. The specific process is to sample and calculate the input antenna signal at high speed to determine the specific delay value. The difficulty of this is that the sampling speed is high, especially for the general software radio platform, which requires A/D and D/A to be more and more Close to the high-frequency (antenna) end, adjust the storage of equivalent bit data with a delay. The larger the storage capacity, the larger the range of adjustable delay, and the difficulty of implementation increases. This factor brings the realization of software radio. difficulty. Therefore, the disadvantages of existing smart antennas are that high-speed signal sampling and calculation are required for technical implementation, the phase (delay) control amount is easily affected, and the control process is relatively complicated.

Invention content:

The purpose of the present invention is to provide a voltage control adaptive antenna with a relatively simple control process to overcome the need for high-speed signal sampling and calculation in the technical implementation of existing smart antennas, the phase control amount is easily affected, and the control process is relatively complicated Defects. The technical scheme of the present invention is: it is made up of N antenna array elements (A1～AN) and a radio wave beam reflector 10, and radio wave beam reflector 10 is arranged on the side of all antenna array elements, and each antenna array element is led by Composed of a directing device 1, a variable dielectric layer 2, a first antenna element 3, a second antenna element 4, an upper electrode 5, a lower electrode 6, and an adjustable voltage DC power supply 7, the first antenna element 3 is fixed on the variable dielectric layer The upper part of the side surface of the body 2 towards the radio wave beam reflector 10, the second antenna vibrator 4 is fixed on the lower part of the side surface of the variable medium layer body 2 towards the radio wave beam reflector 10, and the director 1 is fixed on the variable medium On the side surface of the layer body 2 facing away from the radio wave beam reflector 10, the upper electrode 5 is fixed on the top of the variable medium layer body 2, the lower electrode 6 is fixed on the bottom of the variable medium layer body 2, and the adjustable voltage DC power supply 7 The two output ends of the two output terminals are respectively connected to the upper electrode 5 and the lower electrode 6, and the piezoelectric constant in the direction of the upper electrode 5 and the lower electrode 6 in the variable medium layer body 2 is greater than that perpendicular to the direction of the upper electrode 5 and the lower electrode 6. piezoelectric constant. When the antenna of the present invention works, a transmission signal is input between the first antenna element 3 and the second antenna element 4 and electromagnetic waves are generated, and radio waves are emitted outwards under the reflection of the radio wave beam reflector 10, because each antenna array element The adjustable voltage direct current power supply 7 is set separately in each of them, and the adjustable voltage direct current power supply 7 applies an electric field to the variable medium layer body 2 through the upper electrode 5 and the lower electrode 6 to change the dielectric constant of the variable medium layer body 2, so that The phase characteristics of the radio wave passing through the medium change, which is equivalent to a delay adjustment, and finally changes the direction of the synthesized beam. When the voltage control is adopted, the delay control no longer needs data storage, but changes the propagation speed of the electric wave through the change of the dielectric constant, which also plays a role in delay technically, but the control is very easy to implement and no longer needs Store large amounts of data. Therefore, the control is simplified compared with the traditional way. The invention has the advantages of simple structure, reasonable design, reliable operation and great popularization value.

Description of drawings:

FIG. 1 and FIG. 2 are schematic structural diagrams of existing antennas, FIG. 3 is a schematic structural diagram of the present invention, and FIG. 4 is a top view of FIG. 3 .

Detailed ways:

This embodiment will be described in detail below with reference to FIG. 3 and FIG. 4 . This embodiment is composed of N antenna array elements (A1～AN) and a radio wave beam reflector 10, the N antenna array elements (A1～AN) are arranged in a row, and the radio wave beam reflector 10 is arranged on all antenna array elements On the side, each antenna element is composed of a director 1, a variable dielectric layer 2, a first antenna element 3, a second antenna element 4, an upper electrode 5, a lower electrode 6, and an adjustable DC power supply 7. The first Antenna vibrator 3 is fixed on the upper part of the variable medium layer body 2 towards the side surface of the radio wave beam reflector 10, and the second antenna vibrator 4 is fixed on the lower part of the variable medium layer body 2 towards the side surface of the radio wave beam reflector 10, The director 1 is fixed on the side surface of the variable medium layer 2 facing away from the radio wave beam reflector 10, the upper electrode 5 is fixed on the top of the variable medium layer 2, and the lower electrode 6 is fixed on the variable medium layer 2 The bottom of the adjustable voltage DC power supply 7 is connected to the upper electrode 5 and the lower electrode 6 respectively, and the piezoelectric constant in the direction of the upper electrode 5 and the lower electrode 6 in the variable medium layer 2 is greater than that perpendicular to the upper electrode 5 and the piezoelectric constant of the connection direction of the lower electrode 6. The material of the variable medium layer 2 is a non-linear material with variable dielectric constant, such as liquid crystal or plasma material. Since the control orientation of the radio wave beam needs to have a large range of variation, it is hoped that the variable dielectric layer body 2 will select a material with a large range of dielectric constant variation, and the dielectric constant of liquid crystal and plasma materials will change with the change of the applied voltage. Under the action of the control voltage, the range of change is relatively large. The farther the distance between the upper electrode 5 and the lower electrode 6 is, the higher the control voltage output by the adjustable voltage DC power supply 7 is. The current micro-antenna covering a small area can use a lower control voltage to meet the scanning requirements of the beam. For example, in civil communication, for antennas working in the 2G-3GHz frequency band, under the condition that the directivity of a single vibration source is specified, the distance between the upper electrode 5 and the lower electrode 6 is 10cm, and the variable dielectric layer 2 Liquid crystal material is used, and the variable range of the adjustable voltage DC power supply 7 is about tens of volts to 900 volts. At this time, the range of dielectric constant can be from hundreds to thousands (for example, 500 to 2000). Consider the relationship between the propagation speed of electromagnetic waves and the dielectric constant, and make a rough estimate. If the dielectric constant changes by 4 times, for example, the distance between the upper electrode 5 and the lower electrode 6 is 10 cm, and the thickness of the variable dielectric layer 2 is 1 cm. In the dielectric layer, the phase difference is about π/2. Such beam scanning can reach approximately 2π/3, resulting in different directivities. The above hypothetical estimation does not take into account the changes in the frequency band, antenna size, and directivity of a single vibration source. For specific antennas, specific calculations are required.

In the present invention, different directional antennas are modified, and two positive and negative electrodes are added to the upper and lower ends of the dielectric layer between the antenna vibrator and the phase guider, and the dielectric constant of the piezoelectric medium is changed by changing the DC voltage on the electrodes, thereby The phase characteristics of the radio wave passing through the medium are changed, and finally the direction of the synthesized beam is changed. Although this method is equivalent to delay adjustment, the control process and parameters are simplified. Steering of the receive beam is the same as that of the transmit beam. In consideration of the sensitivity requirement to the electric field, a non-isotropic medium is used on the material of the variable dielectric layer 2, so that the dielectric constant of the variable dielectric layer 2 is sensitive to the applied voltage between the upper electrode 5 and the lower electrode 6. Variations are insensitive to both orientation and vertical. Compared with the traditional antenna, the traditional signal estimation method is adopted, but there is no need to adjust the delay for each signal separately, which simplifies the calculation amount. The number n of array elements in the antenna is variable, and the lobe width of the antenna can be changed by adjusting the value of n. The larger n is, the narrower the lobes are and the better the directivity is. The change in voltage directly controls the angle of the composite lobe.

Claims (2)

1, voltage control adaptive aerial, it is by N bay (A1～AN) form with an electric wave beam reflector (10), electric wave beam reflector (10) is arranged on the side of all bays, it is characterized in that each bay is by director (1), variable dielectric layer body (2), first antenna oscillator (3), second antenna oscillator (4), top electrode (5), bottom electrode (6) and tunable voltage dc power supply (7) are formed, first antenna oscillator (3) is fixed on the top towards the side surface of electric wave beam reflector (10) of variable dielectric layer body (2), second antenna oscillator (4) is fixed on the bottom towards the side surface of electric wave beam reflector (10) of variable dielectric layer body (2), director (1) is fixed on the side surface of the beam reflector of electric wave dorsad (10) of variable dielectric layer body (2), top electrode (5) is fixed on the top of variable dielectric layer body (2), bottom electrode (6) is fixed on the bottom of variable dielectric layer body (2), the piezoelectric constant of top electrode (5) and bottom electrode (6) line direction is greater than the piezoelectric constant perpendicular to top electrode (5) and bottom electrode (6) line direction in two outputs of tunable voltage dc power supply (7) Connect Power the respectively utmost point (5) and the bottom electrode (6), variable dielectric layer body (2).

2, voltage control adaptive aerial according to claim 1 is characterized in that the material selection liquid crystal or the plasma material of variable dielectric layer body (2).

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