CN102881993A - Portable DNA simulation reconfigurable antenna - Google Patents

Abstract

The invention discloses a portable DNA simulation reconfigurable antenna. The structure includes a grounding plate and an active helical metal wire connected to a feed circuit by means of the grounding plate, and also includes an active helical metal wire coaxial with the active helical metal wire. 1. A parasitic helical wire wound on the same helical cylindrical surface and at the same helix angle, and a lumped element is arranged between the active helical wire and the parasitic helical wire. The present invention creates a reconfigurable antenna with a double helix structure. By changing the type and position of the lumped element, two main functions of broadband, high gain and adjustable operating frequency can be realized; the above-mentioned antenna with different functions can be applied to In different antenna systems: Among them, the double helix structure antenna with wide bandwidth and high gain can be used in the radio receiving system, and the bandwidth, gain and axial ratio of the antenna can be optimized by adjusting the size or position of the inductance; A frequency-tunable double helix antenna is used at the transmitting end of the radio.

Description

Reconfigurable Antennas for Portable DNA Simulation

technical field

The present invention relates to an antenna used in the field of radio communication, specifically a portable DNA-simulated reconfigurable antenna, which can realize frequency reconfigurability. the

Background technique

As a component used to transmit and receive radio waves, the antenna plays a pivotal role in the wireless communication system and is an indispensable part of the wireless communication system. With the rapid development of high-frequency satellite communication systems, radar, wireless communication systems, especially the construction of global 3G and 4G networks, the requirements for antennas are getting higher and higher. On the one hand, the antenna needs to be able to work in multiple frequency bands, has a variety of working modes and has good transmission performance; Antennas are considered to be one of the best solutions to the above problems. Reconfigurable antennas are divided into frequency reconfigurable antennas (including realizing broadband and multi-band), pattern reconfigurable antennas, polarization reconfigurable antennas and multi-electromagnetic parameter reconfigurable antennas according to their functions. By changing the structure of the antenna, one or all of the parameters of the antenna, such as frequency, pattern, and polarization, can be reconfigured. In this way, the antenna can have multiple working modes by switching different states of the antenna, which is beneficial to realize various effective diversity in transmission.

At present, the reconfigurable antennas designed by people can be generally divided into two categories: one is to realize the frequency reconfiguration by controlling the physical size of the radiator by the switch, and the other is to change the loading impedance value of the antenna under the control of the switch. , so that its resonant frequency can be changed dynamically. Although various existing methods can achieve frequency reconfigurability to a certain extent, their common disadvantage is that once the antenna is fabricated, it can only be adjusted within a few designed frequency bands.

Contents of the invention

The technical problem to be solved by the present invention is to provide a portable DNA-simulated reconfigurable antenna, which uses a double helix antenna, and by loading different lumped elements at different positions, it is convenient to make a wide bandwidth, high gain antenna characteristic or frequency Frequency reconfigurable antenna with tunable characteristics.

In order to solve the problems of the technologies described above, the technical scheme that the present invention takes is:

A portable DNA simulation reconfigurable antenna, the structure includes a ground plate and an active helical wire connected to the feed circuit by means of the ground plate, and also includes a coaxial and helical cylinder with the active helical wire A parasitic helical wire wound on the same helix angle, and a lumped element is arranged between the active helical wire and the parasitic helical wire.

The parasitic helical wire is connected to the ground plane through a ground capacitor.

On the normal plane of the axis of the active helical wire, the central angle corresponding to the chord between the active helical wire and the parasitic helical wire is α, and 0°<α≤180°.

The α is preferably 30°~120°; more preferably α is 90°.

The lumped elements are inductors or capacitors.

Inspired by the DNA structure, the present invention winds a DNA-simulated double-helix antenna with metal wires, one of which is connected to the feed circuit as an active helical wire, and the other as a parasitic helical wire, (hereinafter referred to as this The invented reconfigurable antenna is called double helix structure antenna for short). For the double helix antenna, due to the strong coupling between the double helixes, the directivity of the antenna will be weakened. The present invention loads a lumped element between two metal conduction strips, which changes the strong coupling between the double helixes. Therefore, high gain antenna. When the type and position of the lumped element are loaded, antennas with different characteristics can be obtained: when the inductor is loaded, the antenna with wide bandwidth and high gain characteristics can be obtained; when the capacitor is loaded, the frequency can be adjusted by changing the vertical height of the capacitor narrowband antenna.

The beneficial effects of adopting the above technical solution are: (1) The present invention creates a reconfigurable antenna with a double helix structure. By changing the type and position of the lumped element, two types of broadband, high gain and adjustable operating frequency can be realized. Reconfigurable antennas with different characteristics; the above-mentioned antennas with different characteristics can be used in different antenna systems: among them, the double helix structure antenna with wide bandwidth and high gain can be used in the radio receiving system, and the bandwidth, gain and axial ratio of the antenna and other indicators It can be optimized by adjusting the size or position of the inductance; the double-helix antenna with adjustable frequency characteristics achieved by loading the capacitor is used at the radio transmitting end, and the operating frequency of the antenna can be continuously adjusted by changing the loading position of the capacitor; (2) The present invention is simple in structure and convenient in reconfiguration, and enables the antenna to have multiple working modes by switching different states of the antenna, which is beneficial to realize multiple effective diversity in transmission; (3) the antenna gain of the two functions of the present invention is very high, 6dB or more; (4) The antennas with the two functions of the present invention realize circular polarization, which is beneficial to signal transmission and reception.

Description of drawings

Fig. 1 is the schematic diagram of the three-dimensional structure of the double helix structure antenna of the present invention;

Fig. 2 is the S11 curve of the single helix antenna, the double helix structure antenna when the inductance is not loaded, and the inductance is loaded;

Fig. 3 is a structural schematic diagram of a matching circuit;

Figure 4 is the S11 curve when the double helix structure antenna is loaded with inductance and the matching circuit in Figure 3 is used;

Fig. 5 is the gain curve when the double helix structure antenna is loaded with inductance;

Figure 6 is the axial ratio curve when the double helix structure antenna is loaded with inductance;

Figure 7 and Figure 8 are the _S11 curves at different vertical heights when the double helix structure antenna is loaded with capacitance;

Fig. 9 is the _S11 curve of simulation and test under 2.4GHz in the second embodiment;

Fig. 10 is the gain curve in the second embodiment;

Fig. 11 is the axial ratio curve of the antenna of the second embodiment;

12 and 13 are schematic diagrams of the component modules of the receiving system and the transmitting system, respectively;

Among them, 1. Active helical wire, 2. Ground capacitance, 3. Parasitic helical wire, 4. Ground plate, 5. Lumped element, 6. Through hole, 7. Microstrip line, 8. Microstrip Line branches.

Detailed ways

Referring to Fig. 1, a frequency reconfigurable antenna based on DNA inspiration, the structure includes a ground plate 4 and an active helical wire 1 connected to the feed circuit through the ground 4, and also includes an active helical wire 3 The parasitic helical wire 1 wound on the same axis, the same helical cylindrical surface, and the same helix angle, and a lumped element 5 is arranged between the active helical wire 3 and the parasitic helical wire 1 . That is to say, both the active helical wire 1 and the parasitic helical wire 3 can be left helical or both are right helical, and both have the same structure and are arranged coaxially, but the position of the starting end on the ground plate 4 is different. the

The parasitic helical wire 3 is connected to the ground plate 4 by means of a grounding capacitor 2, and the grounding capacitor 2 can be a component capable of realizing a capacitive function, for example, a wooden block is used in this embodiment, and the upper surface and the lower surface of the wooden block Metal sheets are uniformly adhered, the metal sheets on the upper surface are connected to the parasitic spiral wire 3 , and the metal sheets on the lower surface are connected to the grounding plate 4 .

On the normal plane of the active helical wire (3) axis, the central angle corresponding to the chord between the active helical wire (3) and the parasitic helical wire (1) is α, and 0°< α≤180°. Taking α as 90° as an example, the performance of the antenna of the present invention is described with test data when different lumped elements are recorded.

In the first embodiment of the present invention, the active helical wire 3 and the parasitic helical wire 1 are first wound, and then the above-mentioned solution is installed and positioned on the ground plate 4, wherein the helical diameter is 26 mm, the height is 126 mm, and the pitch 45mm, the diameter of the metal wire is 2mm, the grounding plate is Rogers5880, and the thickness is 0.508mm. In order to have a more intuitive understanding of the experimental results, a traditional single helix antenna was fabricated, with a helix diameter of 40mm, a height of 150mm, and a theoretical operating frequency of 2.4GHz. Test the S11 curves of the single helix antenna, the double helix structure antenna without inductance, and the inductance loaded, respectively, see Figure 2. It can be seen from the figure that the working bandwidth of the double helix antenna without inductance is narrower than that of the traditional single helix antenna, while the bandwidth of the double helix antenna loaded with inductance is significantly wider than that of the single helix antenna.

The double helix structure antenna of the present invention is still a brand-new field, does not have suitable matching circuit, present embodiment has designed a kind of matching circuit, sees Fig. 3, comprises the microstrip line 7 of cascading in its circuit structure and is arranged on microstrip The function of the two fan-shaped microstrip line branches 8 on one side of the line 7 is to first compensate the imaginary part of the input impedance of the antenna to a small value, but its value is very large, about 150 ohms, and then pass through the fan-shaped microstrip line The stubs and microstrip lines are matched into 50 ohms. The fan-shaped microstrip line stubs are broadband matched, so the broadband characteristics of the antenna are maintained. The matching circuit is etched on the bottom surface of the ground plate 4 and communicated with the active helical wire 3 through the through hole 6 of the metal wall on the ground plate 4 . After the matching circuit is adopted, the simulation of the S ₁₁ curve is shown in Fig. 4. It can be seen from the figure that the operating bandwidth of the antenna is significantly widened after the matching circuit is adopted. It fully demonstrates that the double helix structure antenna of the present invention also has great potential in the field of wide bandwidth antennas.

For traditional single-helix antennas, when the diameter or height of the helix changes, the operating bandwidth increases and the gain decreases, and vice versa; this means that it is difficult to increase both bandwidth and gain at the same time when designing the antenna. For an inductively loaded double helix antenna, both gain and bandwidth can be improved. See Figure 5. The shaded part represents the working bandwidth. For a double-helix antenna with a helix number of 2.8 and a height of 126mm, the gain of 2.0GHz reaches 7.6bB, which is a relatively high gain value, and the working bandwidth is also wide (1.8 ~3.6GHz). Fig. 6 is the axial ratio curve of this embodiment. It can be seen from the figure that it has excellent circular polarization characteristics in the range of 2.2-3.6 GHz.

When studying single-helix antennas, researchers often focus on the bandwidth characteristics, and seldom pay attention to the characteristics of frequency tunability. As the second embodiment of the present invention, when capacitors are loaded at different positions between the two spirals, antennas with different operating frequencies will be obtained.

The skeleton of the double helix structure antenna in this embodiment is different from the above embodiments in that no matching circuit is needed.

The capacitance is horizontally loaded between the active helical wire 1 and the parasitic helical wire 3, the capacitance is 15pF, the vertical height of the capacitance is adjusted continuously, and the _S11 curve is tested, see Fig. 7 and Fig. 8 . It can be seen from the figure that when the capacitor is set at different vertical heights, the working frequency of the antenna is different, and the adjustable frequency range is 2~5.5GHz; There are other frequencies of operation, but with relatively narrower bandwidths. As the vertical height of the capacitor from the ground decreases, the operating frequency increases gradually. For example, the operating frequency of the capacitor at a distance of 33 mm from the ground is 2.6 GHz, and that at a distance of 11 mm from the ground is 4.2 GHz. Using this rule, it can be adjusted at any frequency point within the working frequency band.

Taking the working frequency of 2.4GHz as an example, compare the simulated curve and test curve of S _11. See Figure 9. It can be seen that the simulated working bandwidth is 2.07~2.45, and the actual measured bandwidth is 2.27~2.67. The coincidence of the two curves is Very high. Therefore, after the antenna is prepared, the operating frequency can be selected through software simulation.

Fig. 10 is a gain curve of the antenna of this embodiment, the gain value is smaller than that of the above embodiment, but the gain value is as high as 5dB in most operating frequencies.

Fig. 11 is the axial ratio characteristic of the antenna of this embodiment. The shaded part in the figure is the working bandwidth. It can be seen that within the working bandwidth, the antenna is circularly polarized.

By using the double helix structure antenna of the present invention, a set of radio transmitting and receiving system is constructed to transmit a group of video signals. The radio transmission system (Emission System) includes a camera, a modulation module, a radio frequency mixer module, a power amplifier module and a transmission antenna, see FIG. 12 . Modulation block, RF mixer block and power amplifier block are integrated on one printed circuit board.

The receiving system (Receiving System) consists of 7 parts: receiving antenna, low noise amplifier (Low Noise Amplifier, LNA), down conversion mixing module, demodulation module, video signal output module, AV to USB converter and computer, see figure 13. Among them, the low-noise amplifier, the down-conversion mixing module and the demodulation module are integrated on a printed circuit board.

The video transmission test is carried out in an open space, and the distance between the receiving system and the transmitting system is about 130m. The test results show that the video signal is good and the picture is clear.

Claims (8)

1. the reconfigurable antenna of a portable DNA emulation, comprise ground plate (4) in the structure and be connected the active helical metal wire (3) that ground plate (4) is connected with feed circuit, characterized by further comprising one with active helical metal wire (3) coaxial, with the spiral circle cylinder, with the parasitic helical metal wire (1) of helical angle coiling, between active helical metal wire (3) and parasitic helical metal wire (1), be provided with lamped element (5).

2. the reconfigurable antenna of portable DNA emulation according to claim 1 is characterized in that described parasitic helical metal wire (1) is connected with ground plate (4) by ground capacity (2).

3. the reconfigurable antenna of portable DNA emulation according to claim 1, it is characterized in that at the corresponding central angle of string on the normal plane of active helical metal wire (3) axis, between active helical metal wire (3) and the parasitic helical metal wire (1) be α, and 0 °＜α≤180 °.

4. the reconfigurable antenna of portable DNA emulation according to claim 3 is characterized in that 30 °≤α≤120 °.

5. the reconfigurable antenna of portable DNA emulation according to claim 4 is characterized in that α is 90 °.

6. the reconfigurable antenna of portable DNA emulation according to claim 1 is characterized in that described lamped element (5) is inductance or electric capacity.

7. the reconfigurable antenna of portable DNA emulation according to claim 6 when it is characterized in that described lamped element is inductance, is provided with match circuit between feed circuit and active helical metal wire (1).

8. the reconfigurable antenna of portable DNA emulation according to claim 7 is characterized in that described match circuit comprises the microstrip line and two fan-shaped offset of microstrip line minor matters that are arranged on microstrip line one side of cascade.

Images