RU2769306C1 - Broadband antenna - Google Patents

Abstract

FIELD: technology.

SUBSTANCE: invention relates to antenna technology, in particular to broadband antennas. The effect is achieved by the fact that a broadband antenna containing a vertical conductor installed with the help of the first insulator on the upper end of the tubular base made of a conductive material, a high-frequency matching unit and an input coaxial cable built into the tubular base, and also installed on a horizontal screen and having it is a galvanic contact - a conductive body, on which, with the help of a second insulator, a tubular base is installed with its lower end, and in the housing there is a block of switches and a segment of the transmission line, it differs in that the vertical conductor is made of a pin, and the reactive LC-two-terminal network on adjustable elements and a low-frequency four-pole matching device are introduced into the antenna, placed in a conductive housing and connected by their terminals to the block of switches, at the same time, the ratios of the overall dimensions of the external parts of the antenna are determined.

EFFECT: increasing the efficiency of the action and the radiated power of the antenna in the low-frequency region, as well as expanding the operating frequency range of the antenna towards lower frequencies.

4 cl, 25 dwg

Description

The invention relates to the field of radio engineering and can be used to work with broadband radio transmitting devices.

The broadband antenna, simple in design, has increased energy efficiency in the region of small electrical lengths of its emitter (increased levels of radiation resistance, efficiency and radiated power), and also has an operating frequency range extended towards lower frequencies. The antenna can be used in broadband transmitting communication systems in the shortwave range (from 1.5 to 30 MHz) installed on mobile objects, such as ships, as well as on coastal radio centers.

Known top power antenna /1/, consisting of a vibrator top feed emitter height l, which is its base using a support insulator mounted on a conductive surface. A low-frequency broadband matching device (SHSU), also mounted on a conductive surface, is connected to the emitter input with its output. The input of this SHSU is the input of the entire antenna /1/.

A coaxial power line and a high-frequency broadband matching device (SHSU) are built into the inner cavity of the lower arm of the vibrator radiator, which is made in the form of a non-tunable four-pole ladder chain of reactive elements. Between the base of the emitter and the conductive surface, parallel to the support insulator, a switch is connected that serves to change the feed point of the emitter depending on the selected value of the operating frequency (operating wavelength λ).

The low-frequency control loop contains a four-pole matching circuit and a bypass line, which are connected by their inputs and their outputs using two switches.

The operating wavelength range of the antenna is determined by the ratio 0.05 ≤ l/λ ≤ 1.25, which corresponds to the maximum operating wavelength λ _max =20l and the minimum operating wavelength λ _min =0.8l.

In the high frequency region, where the electrical length of the radiator lies within (0.2-0.25) ≤ l/λ ≤ 1.25, the switch at its base is closed, and the radiator is thereby switched to the upper power supply mode. The bypass line is enabled in the low-frequency SHSU. Antenna matching is carried out by a high-frequency SHSU built into its emitter, due to which the antenna in the high-frequency region operates in a broadband mode without any adjustments and switching.

To operate the antenna in the low-frequency region, where the electrical length of the radiator lies within 0.05 ≤ l / λ ≤ (0.2-0.25), the switch at its base opens and it (the radiator) is switched to the lower power mode, which allows to significantly reduce the shunting effect of the capacitances of the high-frequency SHSU and the coaxial power line built into the emitter. At the same time, the bypass line of the low-frequency SHSU is turned off, and the antenna matching is carried out by the four-pole matching circuit included in this SHSU.

Such an antenna, despite the change in the position of the feed point and the presence of a low-frequency SHSU, has low energy efficiency in the low-frequency region (low efficiency and low level of radiated power), which is explained by the small electrical length of its emitter. So, the radiator of the ship vibrator antenna K-667-001MB with an operating frequency range from 1.5 to 30 MHz, made according to the scheme described in /2/ and used in /1/ (in the version without cylindrical conductors), has, depending on from the design of the antenna, the geometric length is from 10 to 11 m. At a frequency of 1.5 MHz, the electrical length of the emitter l / λ is only 0.05-0.055. As a result, the emitter has a low radiation resistance and a high quality factor, which leads to the need to use switchable or tunable extension inductances of a significant value (up to 100 μH) as part of the four-pole matching circuit of the low-frequency SHSU. The final value of the quality factors of these inductances (usually no more than 60-100 for air coils when they are installed in a closed case of a limited size) in combination with the low radiation resistance of the emitter lead to a significant decrease in the coefficient of performance (COP) of the low-frequency SHSU (up to 25-30% at a frequency of 1.5 MHz). In addition, the efficiency of the emitter itself, with its small electrical length and its use in ship conditions, is no more than 30-40% /3.4/.

Additionally, they reduce the active component of the input resistance of the emitter, and, consequently, the efficiency and gain (KU) of the entire antenna, parasitic capacitances shunting the input of the emitter, the capacitance of the lower insulator, the capacitance of the connector between the emitter and the low-frequency SHSU, as well as the capacitance of the SHSU extension coil on the body devices. The value of the total shunt parasitic capacitance can reach values of 200-300 pF, which leads to an additional decrease in the efficiency and gain of the antenna at the lower frequencies of the operating range by 5-7 dB, i.e. about 3.0-5.0 times.

The cumulative effect of the above negative factors leads to the fact that at a frequency of 1.5 MHz, the efficiency of the antenna /1/ is not more than 2.5-3.5%, and the amount of power radiated by it is not more than 25-35 W (when working with radio transmitter with an output power of 1 kW in a coordinated mode). As a result, the range of short-range communication is significantly reduced, which in the short-wave range is carried out by a surface wave at frequencies from 1.5 to 6-7 MHz, i.e. in the range of small electrical lengths of the emitter 0.05 ≤ l/λ ≤ (0.2-0.25). As a result, a mobile object, such as a sea vessel, after leaving the port very quickly (at a distance of about 300 km) remains without short-wave radio communication, and will not have it until it reaches the communication zone with a sky (ionospheric) wave starting at distance of 700-800 km from the object.

These shortcomings are largely absent in the top feed antenna /5/. The antenna with a total length l contains a top-feed emitter consisting of a vertical conductor with a length of l _pr and a tubular base with a length of l _main made of a conductive material, the vertical conductor being mounted on the tubular base by means of the first insulator.

On the vertical conductor, coaxially with it, there is a set of cylindrical short-circuited conductors intended for frequency-dependent correction of the electric length of the emitter.

The tubular base has an input coaxial cable and a matching unit (high-frequency SHSU), which, like in the antenna /1/, performs matching in the range of electrical lengths of the antenna l/λ ≥ (0.2-0.25). So, for example, for the above short-wave antenna K-667-001MB, the high-frequency SHSU has an operating frequency range from 6.0 MHz (l / λ ≈ 0.2-0.22) to 30 MHz (l / λ ≈ 1.0-1 ,one).

The tubular base with the help of the second insulator with its lower end is mounted on a conductive body with a height h. In the internal cavity of the conductive housing there are two two-terminal networks made up of adjustable RLC-elements (hereinafter referred to as RLC-bipoles), a segment of the transmission line and a switch block that performs all switching of the antenna elements.

The ratio of the length l main of the tubular _base and the height h of the conductive body is selected in the range from 6:1 to 3:1, and the ratio of their diameters (d _main and d _main , respectively) is selected in the range from 1:1 to 1:5.

The ratio of the total length l main of the tubular _base and the height h of the conductive body (l _main + h) to the length l _pr of the vertical conductor is selected in the range from 1:4 to 1:1, which allows you to expand the operating frequency range of the antenna according to the radiation patterns towards higher frequencies .

The diameter of the vertical conductor is selected from design considerations.

The total length of the antenna l is l=l _np +l _main +h.

Antenna /5/, similarly to antenna /1/, has an operating wavelength range determined from the ratio 0.05 ≤ l/λ ≤ 1.25.

In the region of high frequencies, where (0.2-0.25) ≤ l/λ ≤ 1.25, the antenna /5/ works similarly to the antenna /1/ as a top feed antenna. In this case, the second insulator is short-circuited, and the antenna radiator takes the form of a top-feed radiator, and its feed (top) points are the lower end of the vertical conductor and the upper end of the tubular base. Both RLC two-terminals are completely disabled. The input coaxial cable built into the tubular base is connected to a segment of the transmission line located in a conductive housing. The outer end of this segment of the transmission line is the antenna input. Broadband matching of the antenna with the radio frequency cable (and transmitter) is carried out by a matching unit (high-frequency SHSU).

In the low frequency region, where the electrical length of the antenna lies within 0.05 ≤ l/λ ≤ (0.2-0.25), the emitter is switched to the lower power mode. For this purpose, the second insulator is opened using a block of switches, and the lower end of the tubular base becomes the radiator input.

The first of the two-terminal RLCs is connected to the lower end of the input coaxial cable and, through this cable and the high-frequency BCS, is connected to the upper power points. Thus, the antenna radiator in the low-frequency region acquires the configuration of a low-power vibrator with an RLC load included in some of its section, which tunes this radiator to the first (quarter-wave) resonance at the selected operating frequency. In this case, the amplitude of the current in the emitter increases, and the current distribution along the emitter takes a trapezoidal shape instead of a triangular one, which leads to an increase in the current area and, consequently, to an increase in the radiation resistance of the emitter. Depending on the chosen ratio of the length of the vertical conductor 1 _pr and the total length of the tubular base and the height of the conductive body (l _main + h), as well as with minimal losses in the first RLC two-terminal network, the effective length of the antenna radiator /5/ can be increased by 1, 5 times compared with the antenna /1/, due to which the radiation resistance of the antenna emitter increases by about 2.25 times. In this case, the value of the inductive resistance of the first RLC two-terminal network and, consequently, the value of losses in it, increase only 1.5-1.8 times /6/. This leads to an increase in the efficiency of the radiator and the gain of the entire antenna by 1.25-1.5 times, i.e. by about 1.0-1.8 dB.

By changing the adjustable parameters of the first RLC two-terminal network, it is possible to tune the antenna radiator to resonance within the entire low-frequency region.

Unlike the antenna /1/, in the antenna /5/ of all parasitic capacitances shunting the input of the radiator, there is only the capacitance of the second insulator. The value of this capacitance is usually no more than 10-15 pF and does not lead to any noticeable decrease in the efficiency and gain of the antenna, because the capacitance of the antenna emitter with its length of 10-11 m is at least 100-110 pF.

These advantages of the antenna /5/ in the low-frequency region lead to an increase in its efficiency levels and radiated power and, consequently, to an increase in the communication range of the surface wave compared to the antenna /1/.

The presence of losses in the first RLC two-terminal network allows, simultaneously with tuning the antenna to resonance, to expand its bandwidth.

The second two-terminal RLC is connected in series between the radiator input and the transmission line segment and serves to match the resonance-tuned radiator with the RF cable (and transmitter).

Such an antenna is technically the closest to the proposed antenna and can be chosen as a prototype antenna.

However, the prototype antenna has characteristics that prevent obtaining the required technical result, namely:

- the use of the first lossy RLC two-terminal antenna as part of the prototype antenna, although it allows you to tune its emitter to the first (quarter-wave) resonance with a simultaneous expansion of its bandwidth, but limits the magnitude of the current amplitude in the emitter. The presence of losses artificially introduced into the radiator, in combination with its small electrical length, and, consequently, with a small value of its radiation resistance, leads to a noticeable decrease in the level of antenna efficiency and the amount of power it radiates /3/. This makes it practically impossible to expand the operating frequency range of the prototype antenna towards lower frequencies;

- the use of the second RLC-two-pole to match the emitter with the RF cable (and transmitter) does not achieve the goal, since the emitter tuned to the first (quarter-wave) resonance has a purely active input impedance. The value of this resistance is largely determined by the loss in the first RLC two-terminal network /6/ and in the range from 1.5 to 6 MHz with an antenna length of 10-11 m usually lies in the range from one to several tens of ohms. No reactive two-terminal connected in series can transform the indicated active resistances into the active resistance of the RF supply line (usually 50 or 75 Ohms). This is possible only when using a second two-terminal circuit, made in the form of a resistor, the resistance of which complements the indicated values of the input resistance of the emitter to the required value of 50 or 75 ohms. However, this significantly reduces the efficiency of the antenna, while it becomes practically impossible to expand the operating frequency range of the prototype antenna towards lower frequencies. In addition, with a significant level of output power of ship's radio transmitters (from 0.5 to 2 kW), such a matching method is difficult to implement in practice.

To carry out the matching of the prototype antenna due to the reactive component of the resistance of the second RLC two-terminal network, it is necessary to partially detun the radiator of the prototype antenna relative to resonance, which leads to a decrease in the amplitude of the current in the antenna, and, consequently, to a decrease in the efficiency of the antenna and the magnitude of the power it radiates. Thus, both methods of matching the emitter with the help of the second RLC two-terminal network do not allow to significantly increase the energy performance of the antenna;

- cylindrical short-circuited conductors, a set of which is placed on a vertical conductor, are resonant two-poles and correct the electrical length of the emitter only at the frequencies of their quarter-wave resonances. In the bands between these frequencies, there is an increase in the unevenness of the frequency response of the input impedance of the emitter of the prototype antenna, which worsens the conditions for its broadband matching by a matching unit built into the tubular base. In addition, the use of cylindrical short-circuited conductors greatly complicates the design of the antenna, increases its weight and windage.

- the choice of the ratio of the length l main of the tubular _base and the height h of the conductive body in the range from 6:1 to 3:1 and the ratio of their diameters d _main and d _corp in the range from 1:1 to 1:5 makes it possible to implement the conductive body in the form of a significant structure heights with limited transverse dimensions. This complicates the design of the housing, and also leads to an undesirable rise in the lower feed point of the emitter and its actual (emitter) shortening, which reduces the efficiency of the prototype antenna in the low-frequency region.

The presence of the prototype antenna of the above disadvantages greatly reduces its advantage over the antenna /1/. In practice, the magnitude of the efficiency of the prototype antenna (and its radiated power) increases by no more than 1.6-1.7 times. At the same time, the communication range by a surface wave increases by no more than 1.3 times (up to approximately 380–390 km), which does not allow bringing the communication range by a surface wave to the near boundary of the communication zone by a spatial (ionospheric) wave (up to 700–800 km).

Thus, the prototype antenna cannot provide a significant increase in energy efficiency in the region of small electrical lengths of its emitter and any significant expansion of its operating frequency range towards lower frequencies, and also has a complicated design.

In this regard, the aim of the invention is to create a broadband antenna with increased levels of efficiency and radiated power in the low-frequency region (small electrical lengths), as well as extending the operating frequency range of the antenna towards lower frequencies and simplifying the design of the antenna.

The purpose of the invention is achieved by the fact that in a broadband antenna according to claim 1 of the claims, containing a vertical conductor installed with the help of the first insulator on the upper end of the tubular base, made of a conductive material, a high-frequency matching unit and an input coaxial cable are built into the tubular base, as well as a conductive housing mounted on a horizontal screen and having galvanic contact with it, on which, with the help of a second insulator, a tubular base is installed with its lower end, and a switch block and a section of the transmission line are placed in the housing, and the ratio of the total length l of the tubular _base and the height h of the conductive housing (l _main + h) to the length l _pr of the vertical conductor lies in the range from 1:4 to 1:1, the vertical conductor is made of a pin, and the antenna includes a reactive LC-two-pole on adjustable elements and a low-frequency four-pole matching device placed in a conductive housing and connections connected by their terminals with a block of switches, while the ratio of the length of the tubular _base l main and the height h of the conductive body is chosen not to exceed 25:1, and the ratio of the diameter of the conductive body _d to the diameter of the tubular _base d main is chosen not to exceed 100:1.

The newly introduced set of features allows you to implement the following technique:

the introduction of a purely reactive LC-two-pole on adjustable elements and a low-frequency four-pole matching device into the antenna, as well as the choice of the ratio of the length of the tubular _base l main and the height h of the conductive body, allow tuning the antenna radiator into resonance with the maximum possible amplitude and area within the entire low-frequency region current in it, improve the matching of the tuned radiator with the radio frequency cable and more fully use the entire length of the antenna for radiation, which leads to an increase in the radiation resistance of the radiator and the efficiency of the entire antenna, an increase in the level of the radiated power of the antenna and expansion of its operating range towards lower frequencies, while working the antenna wavelength range is 0.04 ≤ l/λ ≤ 1.25, where l is the total length of the antenna and λ is the operating wavelength. The execution of the vertical conductor as a pin and the choice of the ratio of the diameters of the conductive body d _corp and the tubular _base d main make it possible to significantly simplify the design of the antenna radiator, as well as to make the conductive body with a minimum height, which further increases the actual length of the radiating part of the antenna.

When performing a broadband antenna according to claim 2 of the claims, the purpose of the invention is achieved by the fact that the composition of the antenna according to claim 1 of the claims includes a spiral radiator and a third insulator, and the spiral radiator is placed around the tubular base, mainly coaxially with it, and has with it with its upper end, the galvanic contact is predominantly at its upper point, and the lower end of the spiral radiator, using a third insulator mounted on a conductive case, is inserted into the internal cavity of the conductive case and is connected there to the switch block, while the number of turns of the spiral radiator does not exceed 200, the ratio the diameter of the spiral emitter d _izl and the diameter of the tubular base d _main does not exceed 50:1.

The newly introduced set of features allows you to implement the following technique:

the introduction of a spiral radiator and a third insulator into the composition of the antenna makes it possible to make the lower part of the radiator of the proposed antenna spiral in the low-frequency region of the operating range, which significantly increases the electrical length of the antenna radiator. This, in turn, allows you to significantly reduce the resistance of the reactive LC-two-terminal network on adjustable elements, which is necessary to tune the antenna radiator to resonance, and thereby reduce the amount of losses in the adjustable elements of the two-terminal network. Due to this, the efficiency of the antenna and the value of the power radiated by it are significantly increased, the operating frequency range of the antenna is extended towards lower frequencies, while the operating wavelength range of the antenna is 0.35 ≤ l/λ ≤ 1.25.

The ratios given in clause 2 of the claims for selecting the dimensions of the spiral radiator (number of turns and diameter) make it possible to change the electrical length of the spiral radiator in a wide range in the low-frequency region of the operating range, and, consequently, the radiator of the proposed antenna.

When performing a broadband antenna according to claim 3 of the claims, the purpose of the invention is achieved by the fact that in the antenna according to claim 2 of the claims, the spiral radiator is made with taps located predominantly evenly along its length, and the lower ends of the taps with the help of newly introduced additional insulators installed on the conductive body, are passed into the internal cavity of the conductive body and connected there with the switch block, while the number of taps is in the range from 1 to 5.

The newly introduced set of features allows you to implement the following technique:

the implementation of a spiral radiator with taps switched using a block of switches allows you to discretely change the number of turns of this radiator included in the antenna circuit, i.e. the number of its "working" turns, depending on the magnitude of the working wavelength of the antenna. With an increase in the operating wavelength of the antenna, the number of "working" turns of its spiral radiator also increases (discretely), which leads to an increase in the electrical length of the radiator. In this way, within the entire low-frequency region of the operating range, the electrical length of the emitter of the proposed antenna can be made sufficiently close to the resonant (quarter-wave), i.e. carry out a "rough" adjustment of the emitter. This allows, within the entire low-frequency region of the operating range, to significantly reduce the resistance of the reactive LC-two-terminal network necessary for adjusting the radiator, i.e. in fact, use an LC-two-terminal only for “fine” tuning of the antenna radiator to resonance. Consequently, the value of the loss resistance of this two-terminal network will also significantly decrease, which leads to a significant increase in the efficiency of the antenna and the amount of power it radiates, while expanding the operating frequency range of the antenna towards lower frequencies, while the operating wavelength range of the antenna is 0.03 ≤ l / λ ≤ 1.25.

When performing a broadband antenna according to claim 4 of the claims, the purpose of the invention is achieved by the fact that in the antennas according to p.p. 1, 2, 3 claims, the input coaxial cable is formed by the inner surface of the tubular base and a newly introduced conductive rod placed in the inner cavity of the tubular base mainly coaxially with it, the upper end of the rod is connected to the input of the high-frequency matching block, and the lower end of the rod is connected to the block switches.

The newly introduced set of features allows you to implement the following technique:

the introduction of a conductive rod into the antenna and the use of the inner surface of the tubular base as the second conductor of the input coaxial cable makes it possible to make this cable from structural elements, which greatly simplifies the design of the tubular base and the switch block.

The essence of the invention is illustrated by drawings, which shows:

fig. 1 is a diagram of the proposed antenna, made according to claim 1 of the claims;

fig. 2 - diagram of the proposed antenna, made according to claim 2 of the claims;

fig. 3 - diagram of the proposed antenna, made according to claim 3 of the claims;

fig. 4 is a diagram of the proposed antenna, made according to claim 4 of the claims;

fig. 5 - configuration of the proposed antenna, made according to claim 1 of the claims, for the upper frequency region of its operating range;

fig. 6 - frequency characteristics of the input KBV of the proposed antenna and prototype antenna for the upper frequency region of their operating range;

fig. 7 - configuration of the proposed antenna, made according to claim 1 of the claims, for the low-frequency region of its operating range;

fig. 8 - equivalent circuit of the proposed antenna, made according to claim 1 of the claims, for the low-frequency region of its operating range;

fig. 9 - current distribution along the emitters of the proposed antenna, made according to claim 1 of the claims, prototype antenna and analog antenna /1/ for the low-frequency region of their operating range;

fig. 10 - the values of the active and reactive components of the input impedance of the radiator of the proposed antenna, made according to claim 1 of the claims, for several frequencies of the radiator;

fig. 11 - frequency characteristics of the active and reactive components of the input impedance of the radiator of the proposed antenna, made according to claim 1 of the claims, with a smooth adjustment of the radiator within the low-frequency region of its operating range;

fig. 12 - frequency characteristics of the input KBV of the proposed antenna, made according to claim 1 of the claims, for various types of antenna radiator matching within the low-frequency region of its operating range;

fig. 13 - diagram of a matching device for resonant matching of the emitter;

fig. 14 is a diagram of a matching device for broadband matching of an emitter in adjacent frequency bands;

fig. 15 is a diagram of a matching device for broadband matching of the emitter within the entire low frequency region;

fig. 16 - frequency characteristics of the efficiency of the proposed antenna, prototype antenna and analog antenna /1/ for the low-frequency region of their operating range;

fig. 17 - configuration of the proposed antenna, made according to claim 2 of the claims, for the lower frequency region of its operating range;

fig. 18 - equivalent circuit of the proposed antenna, made according to claim 2 of the claims, for the lower frequency region of its operating range;

fig. 19 - embodiment of a spiral radiator with a variable pitch;

fig. 20 - configuration of the proposed antenna, made according to claim 2 of the claims, for the upper frequency region of its operating range;

fig. 21 - configuration of the proposed antenna, made according to claim 3 of the claims, for the lower frequency region of its operating range;

fig. 22 - equivalent circuit of the proposed antenna, made according to claim 3 of the claims, with the helical radiator fully turned on;

fig. 23 - equivalent circuit of the proposed antenna, made according to claim 3 of the claims, with partial inclusion of a helical radiator;

fig. 24 - configuration of the proposed antenna, made according to claim 4 of the claims, for the upper frequency region of its operating range;

fig. 25 - configuration of the proposed antenna, made according to claim 4 of the claims, for the lower frequency region of its operating range.

The proposed broadband antenna according to claim 1 of the claims consists of a vertical conductor 1 (Fig. 1) installed with the help of the first insulator 2 on the upper end of the tubular base 3, made of a conductive material. A high-frequency matching block 4 is built into the internal cavity of the base 3, connected with its output to a vertical conductor 1. An input coaxial cable 5 is connected to the input of the block 4, the outer electrode of which is galvanically connected to the inner surface of the tubular base 3.

The tubular base 3 with the help of the second insulator 6 is mounted on a conductive body 7, which in turn is mounted on a horizontal screen 8 and has galvanic contact with it. In the internal cavity of the conductive housing 7 there is a switch block 9 and a reactive LC two-terminal 10 connected to it on adjustable elements, a low-frequency four-pole matching device 11 (with an input 12 and an output 13) and a segment of the transmission line 14. The lower end is also connected to the switch block 9 input coaxial cable 5, the lower end 15 of the tubular base 3 and the upper end 16 of the conductive body 7.

The second end 17 of the segment of the transmission line 14 is the input of the antenna. The low-frequency four-pole matching device 11, with its common terminal 18, is galvanically connected to the conductive body 7.

The high-frequency matching block 4 is a linear passive electric four-pole circuit. The most preferable, both from the point of view of simplifying the constructive implementation, and from the point of view of achieving the goal of the invention, is its implementation with the structure of a low-pass ladder filter - with inductive longitudinal and capacitive transverse branches.

The low-frequency four-pole matching device 11 is also a linear passive electric four-pole circuit and, depending on its design, can carry out various types of matching:

- resonant (single-frequency) matching within the entire low-frequency region;

- broadband matching in adjacent frequency bands that cover the entire low frequency region in total;

- broadband matching (without any adjustments and switching elements) within the entire low frequency region.

In this case, the matching device 11 can be implemented as a ladder electrical circuit on LC elements (inductances and capacitances) with variable (for the first type of matching) or constant (for the third type of matching) parameters, as well as on elements with mutual inductance (transformers). For the second type of matching, the matching device 11 is implemented as a set of switchable ladder electric circuits on LC elements with constant parameters and elements with mutual induction (transformers). Schemes of the matching device 11 for all three types of matching are shown in Fig. 13-15 and are discussed in more detail below (when describing the operation of the proposed antenna).

In addition to the above options, the implementation of the matching device 11 is also possible on segments of long lines.

The transmission line section 14 can be made in coaxial, symmetrical two-wire or single-wire versions (the second wire in the latter case is the inner surface of the conductive housing 7).

The switch block 9 is most easily implemented on high-frequency electromagnetic relays, for example, vacuum ones, which are produced by the industry, both in open and coaxial versions.

The proposed broadband antenna according to claim 2 of the claims (Fig. 2) additionally contains a helical radiator 19 and a third insulator 20. its upper point 21. The lower end of the spiral radiator 19 with the help of the third insulator 20 passes into the internal cavity of the conductive housing 7 and is connected to the switch block 9. For clarity, in the upper right corner of the figure (Fig. 2) there is a simplified image of the proposed antenna according to p. 2 claims.

The number of turns of the spiral radiator 19 and its diameter are selected from the ratios given in paragraph 2 of the claims. The winding of the turns of the emitter 19 along the tubular base 3 can be uniform or performed with variable pitch. Similarly, the diameter of the radiator 19 may be constant over its entire length or variable.

In the embodiment of the antenna according to claim 3 of the claims (Fig. 3), the spiral radiator 19 is made with taps 22 from its turns, while the lower ends of the taps are passed into the internal cavity of the conductive housing with the help of newly introduced additional insulators 23 installed on the conductive housing and connected there with the switch block 9. The taps 22 are made along the length of the spiral radiator 19 mostly evenly, which allows for a smooth change in the electrical length of the radiator of the proposed antenna when alternately connecting or disconnecting the taps 22.

For clarity, in the upper right corner of the figure (Fig. 3) shows a simplified image of the proposed antenna according to claim 3 of the claims.

In the embodiment of the antenna according to claim 4 of the claims (Fig. 4), the input coaxial cable is formed by a newly introduced conductive rod 24 and the inner surface of the tubular base 3. The conductive rod 24 is placed in the internal cavity of the tubular base 3, mainly coaxially with it. The upper end of the rod 24 is connected to the input of the high-frequency matching block 4, and the lower end of the rod is connected to the switch block 9.

The technical solution claimed in paragraph 4 of the claims for replacing the coaxial cable 5 with a structurally made coaxial cable combined with a tubular base 3 is identical for all three variants of the proposed antenna, made according to paragraphs. 1, 2, 3 claims. In this regard, in FIG. 4 shows a diagram of the antenna, in relation to claim 1 of the claims.

The proposed antenna according to claim 1 of the claims works as follows.

In the upper frequency region of its operating range (0.2-0.25) ≤ l/λ ≤ 1.25, using the switch block 9 (Fig. 1), the following switching is carried out in the antenna. Insulator 6 is short-circuited (at points 15, 16). The lower end of the input coaxial cable 5 is connected to a segment of the transmission line 14. The reactive LC-two-terminal 10 and the low-frequency matching device 11 are completely disabled. The antenna acquires the configuration of the top feed antenna (FIG. 5), which matches the configuration of the prototype antenna for the high frequency region (with the exception of a set of cylindrical short-circuited conductors present in the prototype antenna). The antenna input is the end 17 of the segment of the transmission line 14. The broadband matching of the antenna with the RF cable is provided by the high-frequency matching device 4. The frequency response of the input KBV antenna for this frequency range is shown in Fig. 6 (curve 25). It also shows the frequency response of the KBV prototype antenna (curve 26), which has a significantly greater unevenness due to pronounced resonant properties of cylindrical short-circuited conductors that make up the prototype antenna.

In the low-frequency region of the operating range 0.04 ≤ l/λ ≤ (0.2-0.25) in the antenna, using the switch block 9 (Fig. 1), the following switching is carried out. Insulator 6 opens. The reactive LC-two-pole 10 on adjustable elements is connected to the lower end of the input coaxial cable 5. The low-frequency matching device 11 is connected with its input 12 to a segment of the transmission line 14, and its output 13 is connected to the input of the emitter - point 15.

The resulting antenna configuration is shown in Fig. 7.

The reactive LC-two-terminal 10 through the input coaxial cable 5 and the high-frequency matching device 4 is included in the cross section of the antenna radiator between the lower end 27 of the vertical conductor 1 and the upper point 21 of the tubular base 3. The equivalent circuit of the antenna is shown in Fig. 8, where the two-terminal 28 is the resistance of a circuit composed of a cascade-connected matching device 4 and a cable 5 loaded on the two-terminal 10. All three elements of this circuit are reactive, therefore, the two-terminal 28 also has a purely reactive resistance, the form of which (inductive or capacitance) and the value can be changed by adjusting the LC-elements of the two-terminal 10. In this way, it is possible to ensure the inclusion between points 21 and 27 of reactance with a value that ensures that the antenna radiator is tuned to resonance within the entire low frequency region.

Since, within the low-frequency region, the electrical length of the cascade-connected matching device 4 and cable 5, as a rule, does not exceed 0.25, then in the simplest case, the two-terminal 10 on LC-elements can be made in the form of a variable inductance (variometer or a set of switched inductances ). If the specified electrical length exceeds 0.25, then the two-terminal 10 can be made in the form of a variable (switchable) capacitance in order to ensure the inductive nature of the resistance of the two-terminal 28.

By adjusting the LC-elements of the two-terminal network 10, it is possible to change the value of the inductive resistance of the equivalent two-terminal network 28 (Fig. 8) and thereby adjust the radiator of the proposed antenna to resonance within the entire low-frequency region of the operating range. In this case, the current distribution along the emitter tuned to resonance acquires a characteristic trapezoidal shape (curve 29, Fig. 9), which, as indicated above, increases the radiation resistance of the emitter and leads to a gain in efficiency, gain and the amount of radiated power by about 1.0 - 1.8 dB relative to the classic lower-feed vibrator antennas with a triangular current distribution (curve 30, Fig. 9), including the antenna /1/, which is fed at its lowest point in the low-frequency range. Antenna prototype /5/ when tuned to resonance also has a trapezoidal current distribution (curve 31, Fig. 9), but due to the presence of losses in the elements of its settings, the current amplitude of the prototype antenna is less than that of the proposed antenna. The consequence of this are reduced levels of efficiency and radiated power from the prototype antenna compared to the proposed antenna. Thus, both the classical vibrator antennas of the lower power supply and the prototype antenna are inferior to the proposed antenna in terms of efficiency, KU and radiated power.

In addition, by choosing the ratio of the height and diameter of the emitter of the proposed antenna, respectively, with the height and diameter of its conductive housing 7, it is possible to reduce the height of the housing without changing its volume. This allows you to increase the actual height of the emitter by 5-10% compared to the prototype antenna, which leads to an additional increase in radiation resistance, efficiency and the amount of radiated power by about 10-20%.

At the frequencies of its setting, the radiator of the proposed antenna has a purely active input impedance, which depends on the quality factor of the two-terminal network 28 (and, consequently, the two-terminal network 10) and varies within the low-frequency region from 8-16 to 34-35 Ohm for Q-factor values ranging from 100 up to 300 (resistance values of 8 ohms and 34 ohms correspond to a quality factor of 300, and 16 ohms and 35 ohms correspond to a quality factor of 100). In FIG. 10 shows the values of the active (curves 32) and reactive (curves 33) components of the input impedance of the tuned radiator for several values of its tuning frequencies with an average value of the Q factor of the two-terminal network 28 (about 200). With a smooth restructuring of the adjustable LC-elements of the two-terminal 10, the antenna radiator within the low-frequency region will have, as shown in Fig. 11 are the frequency characteristics of the active (curve 34) and reactive (curve 35) components of the input impedance, the reactive component having a value equal to or close to zero. The low-frequency four-pole matching device 11 transforms (matches) this active resistance into a resistance equal to the characteristic impedance of the input RF cable (usually 50 or 75 ohms). Depending on the technical requirements, the matching device 11, as mentioned earlier, can perform matching of various types - resonant (curves 36 in Fig. 12), broadband in adjacent frequency bands (curves 37) or broadband within the entire low-frequency region (curve 38 ). The diagrams of the matching device 11 for all three types of matching are shown in Fig. 13 (resonant matching), FIG. 14 (adjacent band matching) and FIG. 15 (matching within the entire low frequency region). Here 39 are tunable LC elements; 40 - strip ladder circuits on non-tunable LC-elements 41, operating in adjacent frequency bands; 42 and 43 are series and parallel LC circuits, and 44 are mutually inductive elements. These chains can in principle also be implemented on segments of long lines.

Unlike the prototype antenna, in the proposed antenna, matching is carried out by a four-pole matching device 11 without loss. In this regard, the efficiency of the entire antenna is determined only by the quality factor of the two-terminal 28 and, consequently, the quality factor of the two-terminal 10. In FIG. 16 shows the frequency response of the efficiency of the proposed antenna (curves 45) with a quality factor of the two-terminal 28 equal to 100. Here, for comparison, the frequency response of the efficiency of the prototype antenna (curve 46) is shown under the condition of its full matching (KBV = 1) by the second RLC-two-terminal with losses and the frequency response of the efficiency of the antenna /1/ with a low-frequency matching device (curve 47). From the above characteristics it can be seen that the proposed antenna has a significantly higher level of efficiency (and the amount of radiated power) compared with the prototype antenna and, especially, the antenna /1/. Due to this, the operating range of wavelengths can be extended towards lower frequencies up to l/λ=0.04. Further expansion of the operating range of the proposed antenna towards lower frequencies is limited by a significant increase in the voltage values (and reactive powers) on the elements of the two-terminal network 10 and the high-frequency matching unit 4.

The decrease in efficiency, as well as the KU and the magnitude of the radiated power, of the proposed antenna at low frequencies is explained, first of all, by the small electrical length of the antenna radiator and the finite value of the quality factor of the inductive elements of the two-pole 28 (and the two-terminal 10) necessary to tune this radiator into resonance. To increase the electrical length of the radiator and reduce the loss resistance of the two-terminal 28 (and the two-terminal 10), a spiral radiator 19 (Fig. 2) is introduced into the composition of the proposed antenna according to claim 2 (Fig. 2), which, with its lower end, through the third insulator 20 is connected to the switch block 9 .

The antenna works as follows.

In the low frequency region, where l/λ ≤ (0.2-0.25), the following switching is carried out in the proposed antenna using the switch block 9.

A two-pole 10 is connected to the lower end of the input coaxial cable 5. The insulator 6 opens at points 15, 16, and the lower end of the tubular base turns out to be “hanging in the air”. The radiator input of the proposed antenna is the lower end of the spiral radiator 19, which is connected to the output 13 of the low-frequency matching device 11. The input 12 of the matching device is connected to the conductor 17, which is the input of the antenna. In this case, the configuration of the proposed antenna takes the form shown in Fig. 17. The equivalent circuit of the antenna is shown in FIG. eighteen.

As follows from the equivalent circuit, the spiral radiator 19 electrically lengthens the radiator of the proposed antenna, which leads to a decrease in the inductance of the two-terminal 28 (and the two-terminal 10) necessary for adjusting the radiator and a decrease in the resistance of its losses. This, in turn, leads to an increase in the efficiency of the antenna and the power it radiates, especially at the lowest frequencies.

Improving the energy characteristics makes it possible to expand the operating frequency range of the proposed antenna according to claim 2 towards lower frequencies to l/λ ≥ 0.035.

The use of a spiral radiator 19 due to the choice of the number of its turns makes it possible to tune the radiator of the proposed antenna into resonance within the entire low-frequency region, including at the lowest operating frequency at l / λ ≈ 0.035 with a minimum (zero) resistance of an equivalent two-terminal network 28. However , in this case, the electrical length of the helical radiator 19, and, consequently, the electrical length of the entire radiator of the proposed antenna, become redundant at higher frequencies. Tuning at these frequencies of the emitter in resonance using a two-terminal 10 can become difficult. In this regard, it is advisable to choose such a number of turns of the spiral radiator 19, so that the natural frequency of the first resonance of the radiator of the proposed antenna (without a two-terminal 28) lies in the middle part of the low-frequency region. At the same time, it is possible both to increase the efficiency of the antenna at the lowest frequencies, and to easily tune the radiator into resonance using a two-terminal 10 at higher frequencies. The frequency response of the efficiency of the proposed antenna with this setting is shown in Fig. 16 (curve 48).

Spiral emitter 19 can be made with the same or variable pitch. An example of a transducer with a variable pitch is shown in Fig. 19. Similarly, the helical radiator 19 can be made with a variable diameter, for example, increasing towards the base of the proposed antenna, which is a certain convenience from a constructive point of view.

In the upper frequency region of the operating range (0.2-0.25) ≤ l / λ ≤ 1.25 using the switch block 9 (Fig. 2) in the proposed antenna according to claim 2 of the claims, switching is carried out similar to the switching carried out in the antenna according to claim 1 of the claims. Insulator 6 is short-circuited (at points 15, 16). The lower end of the input coaxial cable 5 is connected to a segment of the transmission line 14. The reactive LC-two-terminal 10 and the low-frequency matching device 11 are completely disabled.

In addition to this, the lower end of the spiral radiator 19 closes on the conductive housing 7 (Fig. 20) and turns out to be shunted by the tubular base 3. Due to this, the antenna according to claim 2 of the claims in the high-frequency region has the same electrical circuit with the antenna according to claim 1 ( Fig. 5) and works similarly to it.

The presence of a shunted helical radiator 19 slightly increases the equivalent diameter of the lower arm of the proposed antenna-tubular base 3, which leads to a slight increase in the level of the input KBV of the proposed antenna according to claim 2 compared to the antenna according to claim 1 of the claims.

The frequency response of the input KBV of the proposed antenna according to claim 2 of the claims for this frequency range is shown in Fig. 6 (curve 49).

In the proposed antenna according to claim 2, the use of a helical radiator 19 with a fixed number of turns provides within the entire low frequency range l/λ ≤ (0.2-0.25) only one natural frequency of the first resonance of the radiator of the proposed antenna. At other frequencies in this region, it is necessary to tune into the first resonance with the help of a two-terminal circuit 28, the resistance value of which and, consequently, the value of the loss resistance in it, can reach significant values. This, in turn, leads to a decrease in the efficiency of the proposed antenna.

To change the number of turns and, consequently, the electrical length of the spiral radiator 19 when changing the operating frequency in the antenna according to claim 3 of the claims along the length of the spiral radiator 19, mainly evenly, taps 22 are made (Fig. 3). The lower ends of the spiral radiator 19 and taps 22 (through insulators 20 and 23, respectively) are connected to the switch block 9.

The antenna works as follows.

In the low frequency region, where l/λ ≤ (0.2-0.25), using the switch block 9 (Fig. 3) in the proposed antenna according to claim 3 of the claims, switching is carried out similar to the switching carried out in the antenna according to p .2 claims. A two-pole 10 is connected to the lower end of the input coaxial cable 5. The insulator 6 opens at points 15, 16, and the lower end of the tubular base turns out to be “hanging in the air”. The input 12 of the low-frequency matching device 11 is connected to the conductor 17, which is the input of the antenna. To the output 13 of the matching device 11 with the help of a block of switches 9 are connected (depending on the value of the operating wavelength) either the lower end of the spiral radiator 19, or the lower end of one of the taps 22. In Fig. 21, for example, the configuration of the proposed antenna is shown when the lower end of the spiral radiator 19 is connected to the output 13 of the matching device 11. The lower ends of the taps 22 remain open and the process of tuning the radiator of the proposed antenna is practically not affected.

When operating at the lowest frequency, in order to ensure the maximum electrical length of the radiator of the proposed antenna, it is necessary to use the full length of the spiral radiator 19 and the lower end of the radiator 19 is connected to the output 13 of the matching device 11. The lower ends of the taps 22 are in the open position. The equivalent circuit of the antenna then has the form shown in Fig. 22. The choice of the number of turns and the diameter of the spiral radiator 19 within the ratios given in paragraph 2 of the claims allows, at the lower operating frequency, to increase the electrical length of the proposed antenna according to paragraph 3 of the claims up to resonant (quarter-wave).

As the operating frequency increases (the operating wavelength decreases), the length of the helical radiator 19 (the number of its turns) becomes redundant. Using the switch block 9, the working length of the spiral radiator is shortened by alternately connecting the lower ends of the taps 22 to the output 13 of the matching device 11, starting from the lower taps to the upper ones. This ensures a reduction in the number of working turns of the spiral radiator (turns included in the radiator circuit of the proposed antenna), and, consequently, a decrease in the electrical length of the radiator of the proposed antenna up to resonant (quarter-wave). In this case, the lower ends of the remaining outlets 22 and the spiral radiator 19 are in the open position.

The equivalent circuit of the antenna for one of the operating frequencies (when one of the taps is connected) has the form shown in Fig. 23.

According to claim 3, the number of taps 22 ranges from 1 to 5. The presence of five taps allows the low frequency region, having an overlap of about 7:1, to be divided into six bands with a relative width of about 38% each. At the same time, in each band, by connecting the required number of turns of the spiral radiator 19 using the appropriate tap 22, the electrical length of the proposed antenna can be selected equal to or close to the resonant quarter-wave length. In this case, the two-terminal 28 (and the two-terminal 10), fine-tuning within each band, will have a minimum value of its resistance and, therefore, a minimum loss, which increases the efficiency, KU and radiated power. The frequency response of the efficiency is shown in Fig. 16 (curve 50).

The implementation of the helical radiator 19 with more than five outlets does not lead to a significant improvement in the electrical characteristics of the antenna and at the same time complicates its design.

The presence of switchable sections makes it possible to maximize the electrical length of the helical radiator 19 at the lowest operating frequency, without redundant electrical length of the same radiator in the upper part of the low frequency range, which makes it possible to expand the range of operating wavelengths to l/λ ≥ 0.03.

In the upper frequency region of the operating range (0.2-0.25) ≤ l / λ ≤ 1.25, using the switch block 9 (Fig. 3), in the proposed antenna according to claim 3, switching is carried out similar to those carried out in the antenna according to p .2 claims. Insulator 6 is short-circuited (at points 15, 16). The lower end of the input coaxial cable 5 is connected to a segment of the transmission line 14. The reactive LC-two-terminal 10 and the low-frequency matching device 11 are completely disabled.

In addition to this, the lower ends of the spiral radiator 19 and all its taps 22 are closed to the conductive housing 7, and the radiator 19 with the taps 22 are shunted by the tubular base 3. Due to this, the antenna according to claim 3 of the claims in the high-frequency region has the same electrical circuit with antennas according to p. 1, 2 (Fig. 5) and works similarly to them.

The presence of a shunted helical radiator 19 with taps 22 somewhat increases, as in the proposed antenna according to claim 2, the equivalent diameter of the lower arm of the proposed antenna - the tubular base 3, while the level of the input KBV of the proposed antenna according to claim 3 practically coincides with similar level of the proposed antenna according to item 2 (Fig. 6, curve 49).

To simplify the design, in comparison with the prototype antenna, in the proposed antenna according to claim 4 of the claims, instead of a separate input coaxial cable 5 (Fig. 1, 2, 3), a conductive rod 24 (Fig. 4) is introduced into the antenna, which together with the inner conductive surface of the tubular base 3 forms a rigid coaxial cable. In this case, the conductive rod 24 is the central electrode of the newly formed cable.

The required value of the wave resistance of this cable is provided by choosing the ratio of the diameters of the inner surface of the tubular base 3 and the conductive rod 24. For example, for a wave resistance of 75 ohms, the ratio of these diameters should be 3.5 /7/. If there is a structural need to reduce the diameter of the rod 24, the inner cavity of the tubular base 3 can be filled with a high-frequency dielectric with an appropriate dielectric constant.

As mentioned above, the technical solution claimed in paragraph 4 of the claims is implemented identically for all three variants of the proposed antenna, made according to paragraphs. 1, 2, 3 claims. In this regard, the operation of the antenna is considered in relation to paragraph 1 of the claims.

The antenna according to claim 4 of the claims works as follows.

In the upper frequency region of its operating range (0.2-0.25) ≤ l/λ ≤ 1.25, using the switch block 9 (Fig. 4), the following switching is carried out in the antenna.

Insulator 6 is short-circuited (at points 15, 16). The lower end of the conductive rod 24 is connected to a segment of the transmission line 14. The reactive LC-two-terminal 10 and the low-frequency matching device 11 are completely disabled. The antenna acquires the top feed antenna configuration shown in FIG. 24 and fully coinciding with the antenna configuration according to claim 1 of the claims shown in FIG. 5.

Obviously, electrically, both antenna configurations (FIG. 24 and FIG. 5) are identical.

In the low frequency region, where l/λ ≤ (0.2-0.25), using the switch block 9 (Fig. 4) in the proposed antenna according to claim 4 of the claims, the following switching is carried out.

Insulator 6 opens. The reactive LC-two-terminal 10 on adjustable elements is connected between the lower end of the conductive rod 24 and the lower end 15 of the tubular base 3. The low-frequency matching device 11 with its input 12 is connected to a segment of the transmission line 14, and its output 13 is connected to the input of the emitter - point 15.

The antenna takes on the configuration shown in Fig. 25 and fully coinciding with the antenna configuration according to claim 1 of the claims shown in FIG. 7.

Obviously, electrically, both antenna configurations (FIG. 25 and FIG. 7) are identical.

BIBLIOGRAPHY

1) Top power antenna. Application 5033093/09 dated March 5, 1992, publ. 06/10/96.

2) Top power antenna. A.s. USSR No. 1663656.

3) Nadenenko S.I. Antennas. - M.: Svyazizdat, 1959. - 552 p., ill.

4) Tarnetsky A.A., Osipov D.D. Ship radio communication antennas. - L .: Sudpromgiz, 1960. - 236 p., ill.

5) Top feed antenna. A.s. USSR No. 1805516.

6) Ovsyanikov V.V. Vibrator antennas with reactive loads. - M.: Radio and communication, 1985. - 120 p., ill.

7) Grodnev I.I., Frolov P.A. Coaxial communication cables. - M.: Radio and communication, 1983. - 208 p., ill.

Claims (4)

1. A broadband antenna containing a vertical conductor installed with the help of the first insulator on the upper end of a tubular base made of a conductive material, a high-frequency matching block and an input coaxial cable built into the tubular base, as well as a conductive cable installed on a horizontal screen and having galvanic contact with it. housing, on which, with the help of the second insulator, a tubular base is installed with its lower end, and a block of switches and a segment of the transmission line are placed in the housing, and the ratio of the total length l of the tubular _base and the height h of the conductive housing to the length l _pr of the vertical conductor lies in the range from 1 : 4 to 1: 1, characterized in that the vertical conductor is made of a pin, and the reactive LC-two-pole on adjustable elements and a low-frequency four-pole matching device are introduced into the antenna, placed in a conductive case and connected by their outputs to the switch block, while ohm, the ratio of the length of the tubular _base l main and the height h of the conductive body does not exceed 25:1, and the ratio of the diameter of the conductive body d _building to the diameter of the tubular _base d main does not exceed 100:1. 2. Broadband antenna according to claim 1, characterized in that the antenna includes a spiral radiator and a third insulator, and the spiral radiator is placed around the tubular base, mainly coaxially with it, and has its upper end in galvanic contact with the tubular base mainly in its upper point, and the lower end of the spiral radiator with the help of a third insulator mounted on a conductive housing is inserted into the internal cavity of the housing and connected there to the switch block, while the number of turns of the spiral radiator does not exceed 200, the ratio of the diameter of the spiral radiator d _izl and the diameter of the tubular base d _main does not exceed 50:1. 3. Broadband antenna according to claim 2, characterized in that the spiral radiator is made with taps located mainly evenly along its length, and the lower ends of the taps with the help of newly introduced additional insulators installed on the conductive housing are passed into the internal cavity of the conductive housing and connected there with a block of switches, while the number of taps lies in the range from 1 to 5. 4. Broadband antenna according to paragraphs. 1, 2, 3, characterized in that the input coaxial cable is formed by the inner surface of the tubular base and the newly introduced conductive rod placed in the inner cavity of the tubular base mainly coaxially with it, and the upper end of the rod is connected to the input of the high-frequency matching block, and the lower end of the rod connected to the switch block.

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