RU2646534C1 - Broadband antenna of very high frequency band - Google Patents

Abstract

FIELD: antenna equipment.

SUBSTANCE: invention relates to radio engineering, namely to antenna engineering and is intended for use as a transceiving antenna together with broadband VHF radio stations. Antenna is made in the form of a hollow metal cone (HMC) 1, mounted vertically above the conductive surface (PP) 2 and facing it vertically. Using dielectric gap (DG) 3 HMC 1 is divided into two parts: lower 4 with height h_L and the upper 4 h_U. Spiral conductor (SC) 6 is installed in the cavity of PMC 1 upper part 5, with possibility of switching of its turns number included in the antenna high-frequency current circuit. Number of turns switching is carried out by means of a switch 7 controlled from the radio station output. By a vertex HMC 1 is connected to the central conductor of the coaxial feeder 11, which screen shell is connected to the PP 2.

EFFECT: technical result consists in extending of the operating frequencies range to the low-frequency region without increasing its physical dimensions.

3 cl, 5 dwg

Description

The invention relates to radio engineering, in particular to antenna technology, and, in particular, an ultra-short-wave (VHF) broadband antenna (ShAA) for use in conjunction with VHF radio stations.

Known ShPA French patent No. 2446090, publ. 04/25/1975 The analogue antenna consists of a biconical vibrator. Logospiral conductors are connected to the base of each of the cones. The coaxial feeder is connected by the central conductor to the top of one of the cones, and the screen sheath to the top of the other cone.

The disadvantage of an analogue is the relatively narrow range of operating frequencies.

ShPA is also known according to the patent of the Russian Federation No. 2207673, publ. June 27, 2003. The antenna consists of a hollow metal cone (PMC) and a conductor located above its top parallel to the plane of the base of the conductor in the form of a one-way flat spiral and a coaxial feeder connected to the PMC.

The disadvantage of this analogue is the relatively narrow range of operating frequencies.

The closest analogue (prototype) in technical essence to the claimed silica gel is the omnidirectional silica gel according to the patent of the Russian Federation No. 2535178 dated 12/10/2014.

The prototype antenna consists of a hollow metal cone (PMC) of height H and with an angle at the apex α. The PMC is mounted vertically above the conductive surface (PP) and faces the top. A spiral conductor (SP) is installed in the PMC cavity in the form of a conical spiral with a height of H _C and an angle β at the apex. The top of the conical spiral is connected to the inner surface of the PMC at its top. The coaxial feeder is connected by the central conductor to the top of the PMK, and the screen sheath to the PP.

The disadvantages of the prototype are:

relatively small working frequency range by agreement, characterized by the value of the traveling wave coefficient (KBW).

The aim of the invention is the development of a broadband VHF antenna, providing an extension of the operating frequency range in the low frequency region.

The specified technical result is achieved by the fact that in the well-known silos of the VHF range, containing a PMC of height N and with an angle at the apex α, mounted vertically above the PC and facing the apex, a spiral conductor (SP) installed in the PMC cavity and a coaxial feeder connected the central conductor to the top of the PMC, and the shield to the PP, the PMC is divided by a dielectric gap (DZ) Δ into a lower height h _H and an upper height h _B part. The joint venture is made with the possibility of switching the number of its turns and is connected at one end to the edge of the lower part of the PMC adjacent to the DZ. N≥2 turns of SPs are equipped with leads that are connected to the corresponding N inputs of the switch of turns of SPs. The high-frequency (including) output of the switch is connected to the edge of the lower part of the PMK adjacent to the DZ. N - bit control input of the switch is connected to the control output of the radio station.

The height H of the PMC is selected from the condition H≥0,2λ _max , where λ _max is the maximum wavelength of the working range of the antenna waves. The ratio of the heights h _H and h _{B is} selected in the range h _H / h _B = 0.4-0.55, and the angle α is selected in the range α = 80 ° -100 °. The joint venture is installed in the cavity of the upper part of the PMC.

Due to the new set of essential features when operating the antenna in the frequency range by switching the number of turns of the joint venture connected to the remote sensing element, the electric height of the conical radiator is changed, which improves the quality of matching and, therefore, provides an extension of the operating frequency range to the low-frequency region.

The claimed antenna is illustrated by drawings, which show:

in FIG. 1 - general view of the antenna;

in FIG. 2 - electrical circuit of the switch;

in FIG. 3 is a drawing explaining the operation of the antenna;

in FIG. 4 is an equivalent antenna circuit;

in FIG. 5 - results of comparative measurements;

quality approval - IPM.

The claimed VHF VHF range shown in FIG. 1, consists of a PMC 1 of height H and with an angle α at the apex. PMK 1 is installed vertically above PP 2 and faces the top. Using a dielectric gap 3, made, for example, in the form of a dielectric insert of thickness Δ, the PMC 1 is electrically divided into two parts: the lower 4 with a height of h _H and the upper 5 with a height of h _B. In the cavity of the upper part 5 of PMC 1, SP 6 is installed in the form of a multi-turn inductor. In the general case, SP 6 can also be installed in the cavity of the lower part of PMK 1. The choice of the installation site of SP 6 is determined from design considerations. N≥2 turns of SP 6 are equipped with terminals 6 ₁ -6 _N , which are connected to the corresponding N inputs of switch 7 of SP 6 (Fig. 1 shows five terminals, i.e., N = 5). Terminals 6 ₁ -6 _N can be provided with all turns or some of them. The choice of the number N of turns equipped with terminals 6 ₁ -6 _N is determined based on the condition of maintaining the required quality of matching in the operating frequency range.

V.ch. the output 7.1 of the switch 7 is connected (point “k”) to the edge of the upper part 5 of the PMC 1 adjacent to the DZ 3; the N-bit control input 7.2, the switch 7 is connected to the control output of the radio station through the hole 9 in the PMC 1 through the hole 9 (not shown in FIGS. 1, 2).

Input 6.6 SP 6 through the hole 10 in the DZ 3 is connected to the edge of the lower part 4 of the PMC 1 adjacent to the DZ 3 (point "a").

The switch 7 is designed to connect (disconnect) the corresponding number of turns of the joint venture 6, in the circuit v.ch. current PMK 1 depending on the sub-band of operating frequencies within which the radio station operates. The electrical circuitry of the switch can be implemented in various ways, in particular, as shown in FIG. 2. The switch 7 consists of N automatic switches 7.3 ₁ -7.3 _N (in Fig. 2 N = 5), with which they change the value of the inductance of the joint venture 6, included in the RF PMK circuit 6. A control signal for connecting (disconnecting) the corresponding contact 7.4 of the automatic switch 7.3 is supplied via an N-bit cable 8 to the actuator 7.5 from the control output of the radio station (not shown in Fig. 1, 2).

Coaxial feeder 11 is connected by a central conductor to the top of PMK 1 (point “c”), and by a screen sheath to PP 2 (point “c”).

The claimed antenna operates as follows.

When you turn on the radio in the section of the points "c-in" connecting the coaxial feeder 11 (see Fig. 2) EMF is excited. Depending on the selected operating frequency sub-band, a control signal is supplied via the N-bit bus 8 to connect the corresponding group of turns of the joint venture 6. In FIG. 2 shows, in particular, that the contact 7.4 of the automatic switch 7.3 ₃ is closed. This means that in the chain v.ch. current, the inductive resistance X _{L of the} part of the joint venture 6 is turned on from point “a” to the point of connection of terminal 7.2 (see also Fig. 4).

Under the influence of exciting emf the conductivity current I _pr flows from point “c” along the generatrix of the outer surface of the lower part 4 of PMC 1, then along its upper edge to point “c” of connection of terminal 6.6 of SP 6 (see Fig. 3 and Fig. 1). Then current flows through the conductors of the connected turns and through a closed contact to the point “k” of the joint venture 6 to the edge of the upper part 5 of the PMC 1. Further, including the conduction current flows along the generatrix of the outer surface of the upper part 5 of the PMC 1 and is closed from its upper edge by bias currents I cm to PP 2, flows along it with conduction currents to the points “c-s” of connecting the screen sheath of the coaxial feeder 11 (see Fig. 3 )

Thus, the equivalent antenna circuit shown in FIG. 4, consists of series-connected: the complex resistance Z _{H of the} lower part 4 of the PMC 1, the reactance of the inductive nature of the connected turns of the joint venture 6 and the complex resistance Z _{B of the} upper part 5 of the joint venture 6. Commuting the number of turns included in the circuit the current, you can change the values of X _L and, therefore, it is possible in a wide range of operating frequencies of the antenna to shift the working range by agreement to the low-frequency region; thereby preserving the required level of CBM, which for VHF radio stations is received at the level of CBM≥0.4.

The ratio of the structural elements of the silo VHF range, at which the specified technical result is achieved, were determined experimentally and amounted to

h _H / h _B = 0.4-0.55; H≥0.2 λ _max ; α = 80 ° -100 °; the number of turns N SP 6 is selected based on the possibility of achieving the inductive resistance value X _L , providing an equivalent increase in the electric height of the PMC, at which the value of the KBV≥0.4 is maintained. In the claimed antenna, the total length of the wire SP 6 is (2.5-4) N.

The optimal design parameters are the average values of the above intervals of these parameters.

An experimental verification of the feasibility of achieving the specified technical result was carried out by comparative measurements of the quality of coordination (KBM) of the declared silo under the following conditions:

For the claimed silos: λ _max = 2 m; feeder wave resistance ρ _f = 50 Ohm; H = 0.4 m; h _H = 0.2 m; h _B = 0.2 m; the wire length of the turns was 2.5 m; number of turns N = 8, wire diameter - 2 mm; α = 80 °; fiberglass dielectric insert Δ = 5 mm.

For the prototype: λ _max = 2 m; ρ _f = 50 Ohms; H-0.4 m; α = 80 °; the wire length of the turns was 1.5 m; wire diameter 2 mm.

включенных в цепь в.ч. токов, без увеличения физической высоты Н ПМК.The measurement results shown in FIG. 5, provide the basis for the following conclusions. With equal physical heights of the declared silos and the prototype of the declared antenna, the level of KBV≥4 is provided, starting with the electrical size N / λ = 0.12 of the prototype with N / λ = 0.19. The extension of the working range of the antenna as agreed to the lower frequency region is ensured by a threefold change in the number of turns of SP 6 and, therefore, the values of reactance

included in the chain currents, without increasing the physical height H PMK.

The obtained results of comparative measurements confirm the feasibility of achieving the specified technical result when using the claimed silo.

Claims (3)

1. Broadband antenna (SLA) of the ultra-short wave (VHF) range, containing a hollow metal cone (PMC) of height H and with an angle at apex α, mounted vertically above the conductive surface (PP) and facing the apex, a spiral conductor (SP) installed in the PMC cavity, and a coaxial feeder connected by a central conductor to the top of the PMC, and a screen sheath to the PP, characterized in that the PMC is divided by a dialectic gap (DZ) Δ into two parts: the lower height h _H and the upper height h _B , the joint venture is configured to commutation the number of its turns and is connected at one end to the edge of the lower part of the MVC adjacent to the DZ, N≥2 turns of the SP are equipped with leads that are connected to the corresponding N inputs of the switch of the turns of the SP, the high-frequency output of which is connected to the edge of the bottom of the MVP adjacent to the DZ, and N- the bit control input of the switch is connected to the control output of the radio station. 2. The VHF antenna according to claim 1, characterized in that the height H of the PMC is selected from the condition H≥0.2λ _max , where λ _max is the maximum wavelength of the working range of the antenna waves. 3. The VHF antenna according to claim 1, characterized in that the ratio of the heights h _H and h _{B is} selected in the range h _H / h _B = 0.4-0.55, and the angle α is selected in the range α = 80 ° -100 ° .

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