RU2099828C1 - Plane resonant antenna - Google Patents

Abstract

FIELD: antenna engineering; reception of frequency-modulated ratio and TV broadcasting signals; radar and radio communication systems. SUBSTANCE: antenna operating in 25 to 1000 MHz frequency range has open cavity in the form of multiturn arithmetic spiral mounted on insulating base; coupling turn placed is around spiral is a spaced relation to internal and external conductors of coaxial feeder series-connected to matched load whose impedance equals wave impedance of coaxial feeder. Start of spiral is connected to internal conductor of coaxial feeder; spiral conductor length is a multiple of half the maximum working wavelength in open cavity; coupling turn length equals

, where λ₁ is maximum wave length of working range turn is external relative to spiral. EFFECT: extended working frequency range of antenna; improved matching of the latter with its feeder. 4 dwg

Description

 The invention relates to antenna technology and can be used as a small-sized broadband antenna for receiving FM broadcasting signals, television broadcasting in the meter and decimeter wavelength ranges, as well as in radio detection systems and in connected radio systems for various purposes.

 Known flat resonant antennas, consisting of a set of series-connected loop asymmetric vibrators tightly wound around a common center, located radially on a dielectric base [1] The implementation of the receiving system from a series of series-connected tightly wound around a common center loop conductors allows to obtain a compact antenna design. The presence of a large number of series-connected loop vibrators of various lengths allows for the implementation of a multi-resonant characteristic of the input impedance of the antenna and broadband properties.

 Common features with the proposed device are the implementation of the antenna in the form of a series of bent and tightly wound around a common center conductors located on a dielectric base, which determines the resonant and broadband properties of the antenna.

 However, the known flat resonant antennas do not provide the omnidirectionality of the reception characteristics of the signals, since they have a deep zero in the radiation pattern. In addition, the complexity of the antenna excitation circuit does not allow to practically realize the broadband of the radiating structure.

The closest to the invention in terms of technical nature and the technical result achieved is a flat resonant antenna containing an open resonator in the form of a multi-turn arithmetic spiral made of a tape conductor on a dielectric base, while the width of the gaps between the turns of the spiral is chosen to be the same and equal to the width of the tape conductor of the spiral, and communication coil connected to the internal and external conductors of the coaxial feeder [2]
The common features of this and the proposed antennas are the presence of an open resonator in the form of a multi-turn arithmetic spiral, which is made of a tape conductor located on a dielectric base, while the width of the gaps between the turns of the spiral is chosen to be the same and equal to the width of the tape conductor of the spiral, and the communication loop connected to internal and external conductors of the coaxial feeder. The implementation of the open resonator conductor in the form of a multi-turn arithmetic spiral with the specified gap width and the location of the coupling loop in the inner region of the resonator reduce the dimensions of the resonant antenna.

 However, the known flat resonant antenna is narrow-band, since the relative position of the antenna conductors does not allow to expand the range of operating frequencies in the direction of long waves by increasing the number of turns n of the spiral more than four. This is explained by the fact that when n> 4, the magnitude of the inductive coupling of the spiral with the coupling loop decreases both by reducing the electrical dimensions of the coupling coil and by removing peripheral spiral coils from it. This leads to a sharp drop in the radiation resistance of the antenna, which makes it difficult to match its input impedance with the impedance of the coaxial feeder.

 The invention solves the problem of creating a broadband receiving plane of the antenna, covering the range of meter and decimeter waves, having a simple and compact design in these ranges, which allows the antenna to be covertly placed in rooms and on vehicles, and having omnidirectional properties in the plane of the antenna.

, а ширина W₁ ленточного проводника витка связи выбрана равной w₁ = 0,03λ₂, где λ₁ наибольшая длина волны рабочего диапазона, λ₂ наименьшая длина волны рабочего диапазона; начало проводника арифметической спирали подключено к внутреннему проводнику коаксиального фидера, длина ленточного проводника арифметической спирали выбрана кратной половине наибольшей рабочей длины волны в открытом резонаторе, а ширина W₂ ленточного проводника арифметической спирали выбрана равной w₂ = 0,01λ₂.This is achieved by the fact that in a flat resonant antenna containing an open resonator in the form of a multi-turn arithmetic spiral made of a tape conductor on a dielectric base, the width of the gaps between the turns of the spiral is chosen to be the same and equal to the width of the tape conductor of the spiral, and the communication coil connected to the internal and external conductors of the coaxial feeder, the communication coil is made in the form of a ribbon conductor, covering a spiral with a gap, the width of which is equal to the width of the gaps between the turns of the arithmetic a spiral, in this case, a gap is made in the middle of the communication loop, in which a matched load is included, the resistance of which is equal to the wave resistance of the coaxial feeder, and the length l _{1 of the} communication coil is chosen equal to

and the width W _{1 of the} ribbon conductor of the communication loop is chosen equal to w ₁ = 0.03λ ₂ , where λ _{1 is the} longest wavelength of the operating range, λ _{2 the} smallest wavelength of the working range; the beginning of the arithmetic spiral conductor is connected to the inner conductor of the coaxial feeder, the length of the ribbon conductor of the arithmetic spiral is selected to be a multiple of half the maximum working wavelength in the open resonator, and the width W _{2 of the} ribbon conductor of the arithmetic spiral is selected to be w ₂ = 0.01λ ₂ .

 The proposed antenna due to its broadband can be used to receive signals as FM broadcasting and television, and in the operating frequency ranges of communication systems for various purposes. The compact design and small dimensions, as well as the omnidirectional characteristics of the radiation, allow it to be used as a broadband room television antenna, when telescopic type vibrator antennas are usually used, and in the decimeter range, directional antennas with passive vibrators. The flat design of the proposed antenna allows you to discreetly place it on the roof of the car, and its broadband properties allow you to use it as an all-wave antenna instead of the currently used narrow-band whip antennas.

 In the implementation of the invention, the operating frequency range of the antenna is expanded and its coordination with the coaxial feeder is improved. In this case, an omnidirectional diagram with a small indentation in the plane of the antenna is realized in a wide frequency band.

 No solution was found for a flat resonant antenna, in which the coupling coil was located in the outer region of the open resonator and was discontinuously loaded to a matched load whose resistance was equal to the wave impedance of the coaxial feeder, and which would have a geometry (electrical dimensions) identical to the geometry of the proposed antenna . This provides an extension of the working range of the antenna and improved matching with the coaxial feeder. Therefore, the proposed solution meets the criteria of an inventive step.

In FIG. 1 shows a General view of the proposed flat resonant antenna; figure 2 shows the placement of the antenna on the metal surface of the roof of the vehicle; figure 3 shows the flow of currents along the conductors of the antenna; figure 4 presents the results of an experimental study of the frequency dependence of the VSWR of the proposed antenna at the output of the supply coaxial feeder with a wave impedance of Z ₀ 50 Ohms.

, где N 1,2,3. Λ₁ наибольшая рабочая длина волны в открытом резонаторе. Для открытого резонатора в виде многовитковой арифметической спирали, выполненной на диэлектрическом основании с зазором между витками Δ₂ = w₂, длина волны Λ₁ может быть определена как

где λ₁ наибольшая длина волны рабочего диапазона в свободном пространстве;
ε_r относительная диэлектрическая проницаемость материала диэлектрического основания 7.The proposed flat resonant antenna consists of an open resonator 1, a coupling coil 2 and a coaxial feeder 3. The open resonator 1 is made in the form of an arithmetic spiral 4 with the number of turns n>1.25; which are located in the same plane around the common center 5. The turns of the spiral 4 are made of a ribbon conductor 6 located on the dielectric base 7. The width w _{2 of the} ribbon conductor of the spiral 4 is chosen equal to w ₂ = 0.01λ ₂ , where λ ₂ is the shortest wavelength of the working range. The width Δ _{2 of the} gaps between the turns of the spiral 4 is chosen equal and equal to Δ ₂ = w ₂ . The length l _{2 of the} tape conductor 6 of the spiral 4 is chosen equal

where N 1,2,3. Λ _{1 is the} largest working wavelength in an open resonator. For an open resonator in the form of a multi-turn arithmetic spiral made on a dielectric base with a gap between the turns Δ ₂ = w ₂ , the wavelength Λ ₁ can be defined as

where λ _{1 is the} largest wavelength of the working range in free space;
ε _{r the} relative dielectric constant of the material of the dielectric base 7.

. Рамка может иметь круглую, квадратную или прямоугольную форму. Ширина w ленточного проводника 10 витка связи 2 выбрана равной w₁ = 0,03λ₂. Ширина Δ₁ зазора 11 выбрана равной Δ₁ = Δ₂ В середине витка связи 2 выполнен разрыв 12, в который включена согласованная нагрузка 13, сопротивление R_н которой выбрано равным R_н Z₀, где Z₀ волновое сопротивление коаксиального фидера 3. Виток связи 2 подключен к точкам ab ввода 14 антенны. К точкам ab ввода 14 также подключены проводники 8 и 9 коаксиального фидера 3. Ленточные проводники 6 и 10, а также ввод 14 антенны располагаются на диэлектрическом основании 7. Они могут быть выполнены методом травления (печатной технологии) с использованием фотошаблона и фольгированного высокочастотного диэлектрика типа стеклотекстолита толщиной h 0,5.2,0 мм или методом напыления на тонкой (h 50 мкм) полиэтилентерефталатной пленке.The beginning of the tape conductor 6 of the arithmetic spiral 4 is connected at the point a to the inner conductor 8 of the coaxial feeder 3. The coupling coil 2 is a frame made of a tape conductor 10, covering the spiral 4 with a gap 11 and combined with it in the same plane. The total length l _{1 of the} frame is chosen equal to l ₁ 2S ₁ + 2S ₂

. The frame may have a round, square or rectangular shape. The width w of the tape conductor 10 of the connection loop 2 is chosen equal to w ₁ = 0.03λ ₂ . The width Δ _{1 of the} gap 11 is chosen equal to Δ ₁ = Δ _2. In the middle of the communication loop 2, a gap 12 is made, in which a matched load 13 is included, the resistance R _{n of} which is chosen equal to R _n Z ₀ , where Z _{0 is the} wave resistance of the coaxial feeder 3. Communication loop 2 is connected to the ab points of input 14 of the antenna. Conductors 8 and 9 of coaxial feeder 3 are also connected to ab points of input 14. Ribbon conductors 6 and 10, as well as antenna input 14 are located on dielectric base 7. They can be made by etching (printing technology) using a photo mask and foil type high-frequency dielectric fiberglass with a thickness of h 0.5.2.0 mm or by spraying on a thin (h 50 μm) polyethylene terephthalate film.

 Such a flat antenna made on a film can be mounted on the roof 15 of a vehicle, for example, a car, using an adhesive layer 16, as shown in FIG. From above, it can be covered with a thin layer of radiolucent paint, which makes it almost invisible. Input 14 of the antenna through the window opening 17 of the vehicle is led into its cabin, where the feeders 8 and 9 are connected to it. Due to the small thickness of the film version of the proposed antenna, it can be covertly placed on the roof or other external surfaces of the vehicle, as well as on flat surfaces both inside and outside the building of the receiving point without deterioration of electrical characteristics.

где N 1,2,3.The proposed flat resonant antenna operates as follows. The electromagnetic wave incident on the open resonator 1 excites in the conductor 6 of the open resonator 1 standing current waves resonating at a frequency at which the condition

where N 1,2,3.

 Λ wavelength in an open resonator.

где N 1,2,3.Due to inductive coupling between the conductor 6 of the open resonator 1 and the coupling coil 2, as well as conductive coupling at the point a of the conductor 6 with the coupling coil 2, at the points ab of the connection of the coupling coil 2 to the coaxial feeder 3, an EMF is generated that excites electromagnetic energy oscillations propagating in form of a TEM wave by coaxial feeder 3 to the receiver. Since the length l _{2 of the} conductor 6 of the open resonator 1 is selected to be a multiple of half the largest working wavelength in the open resonator, the resonance condition (2) will be satisfied for many shorter waves when an integer number of standing half waves will fit along conductor 6. To reduce the resonant increase in the input resistance of the antenna, the width of the tape conductor 6 of the spiral 4 is chosen equal to w ₂ = 0.01λ ₂ . This decreases the wave resistance of the oscillatory circuit, equivalent to an open resonator. Thus, the proposed antenna in its principle of operation is multi-resonant, and therefore broadband. The resonant wavelengths of the antenna are determined from (2) as

where N 1,2,3.

, а ширина w₁ = 0,03λ₂. Трансформация R_Σ проводника 6 ко входу питающего фидера осуществляется при большом числе витков спирали 4 (n > 1,25), то есть в широкой полосе частот. Объясняется это тем, что виток связи 2 охватывает спираль 4, а поэтому имеет с ней индуктивную связь на участке большой протяженности и, кроме того, проводник 6 спирали 4 имеет в точке а кондуктивную связь с витком 2. Это облегчает согласование предлагаемой антенны с питающим коаксиальным фидером в широкой полосе частот. Для обеспечения в питающем фидере 3 режима бегущих волн в середине витка связи 2 включена согласованная нагрузка 13, сопротивление которой R_н Z₀. Это улучшает согласование антенны с питающим коаксиальным фидером в широкой полосе частот, что подтверждается экспериментальными данными частотной зависимости КВСН антенны, представленными на фиг.4. Диапазон рабочих частот предлагаемой антенны от 25 до 1000 Мгц.The radiation resistance R _Σ that arises during resonances of the conductor 6 is transformed into a communication coil 2, and the input ab of the antenna feeder 3 is loaded on it. To increase the efficiency of communication loop 2, its length is chosen equal to

and the width w ₁ = 0.03λ ₂ . The transformation of R _{Σ of the} conductor 6 to the input of the feeder is carried out with a large number of turns of the spiral 4 (n> 1.25), that is, in a wide frequency band. This is explained by the fact that the coupling loop 2 covers the spiral 4, and therefore has inductive coupling with it over a long section and, in addition, the conductor 6 of the spiral 4 has conductive coupling at the point a with the coil 2. This facilitates matching of the proposed antenna with the supply coaxial feeder in a wide frequency band. In order to ensure traveling wave modes in the supply feeder 3, a matched load 13 is included in the middle of the connection loop 2, the resistance of which is R _n Z ₀ . This improves the alignment of the antenna with the supply coaxial feeder in a wide frequency band, which is confirmed by the experimental data of the frequency dependence of the VSWR antenna, presented in figure 4. The operating frequency range of the proposed antenna is from 25 to 1000 MHz.

Placing the proposed flat resonant antenna on a metal surface (figure 2) fundamentally does not violate the regime of traveling waves in the feeder 3 and does not significantly change the nature of the matching of the antenna with the feeder, but only shifts the coordination curve in the direction of long waves. This is because the spiral conductor 6 of the resonator 1 acquires an additional distributed capacitance, which increases the effective relative permittivity e _{r of the} dielectric filling of the resonator and, in accordance with (1), reduces the resonant wavelength Λ ₁ . This allows for a given antenna size to advance into the region of longer waves. With an increase in the number of turns n of spiral 4, the number N of standing current waves stacked along conductor 6 increases. This evens out the current distribution in the spiral plane. At n ≥ 3, the current distribution approaches uniform, and the radiation pattern in the antenna plane becomes almost omnidirectional.

 With increasing n, the indentation of the omnidirectional diagram of the proposed antenna decreases. In addition, the current flowing through the conductor 6 has the opposite direction on opposite sides of the spiral (see Fig. 3). Therefore, in the direction normal to the plane of the antenna passing through its center 5, the radiation of the current turns of the spiral is compensated, and the antenna pattern in this direction has a zero field value.

несимметричного вибратора с экраном (противовесом).Thus, when placing the proposed flat resonant antenna on a metal surface, the radiation characteristic of the antenna is similar to the radiation characteristic

asymmetric vibrator with a screen (counterweight).

The implementation of the open resonator conductor in the form of a multi-turn arithmetic spiral connected to the inner conductor of the supply coaxial feeder and having a length that is a multiple of half the largest working wavelength in the open resonator, and the coupling loop in the form of a ribbon conductor enclosing the spiral with a gap and loaded in gap to the matched load , the resistance of which is R _n Z _o , allows you to expand the operating frequency range of the antenna and improve its coordination with the supply coaxial feeder.

LITERATURE
(56) 1. US patent N 4318109, CL. H 01 Q 9/00, 1991.

 2. SU, copyright certificate N 1681357, cl. H 01 Q 9/00, 1991.

Claims (1)

A flat resonant antenna containing an open resonator in the form of a multi-turn arithmetic spiral made of a tape conductor on a dielectric base, while the gap width between the turns of the spiral is chosen to be the same and equal to the width of the tape conductor of the spiral, and a communication coil connected to the inner and outer conductors of the coaxial feeder, characterized in that the communication coil is made in the form of a ribbon conductor, covering an arithmetic spiral with a gap, the width of which is equal to the width of the gaps between the vit kami arithmetic spiral, while in the middle of the coil connection is formed a gap, which includes matched load, whose resistance is equal to the characteristic impedance of the coaxial feeder, the length L ₁ loop connection is chosen equal to l ₁ = λ _1/8, and the width w ₁ of the strip conductor coil connection is selected equal to w ₁ = 0,03λ _2, where λ ₁ - the maximum length of the working wave range, λ ₂ - the smallest length of the operating range of the wave conductor arithmetic start helix connected to the internal conductor of the coaxial feeder, the length of the tape wire Single arithmetic spiral selected half times the maximum operating wavelength in the open resonator and the width w ₂ arithmetic spiral strip conductor is chosen equal to ₂ w ₂ = 0,01λ .k

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