JP2006093762A - Dipole antenna system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dipole antenna system for blocking radio wave disturbance due to harmonics from the antenna acting like a phased array antenna for emitting a radio wave signal in an optional direction in a space as a radio wave beam with radiation directivity from an amplifier via a coaxial feeder and an impedance converter. <P>SOLUTION: The dipole antenna comprises an antenna base 10 wherein horizontal extension rods 14, 15 are fixed to an upper end part of a hollow outer conductor 12 and a center conductor member 18 is arranged in a hollow inside of the outer conductor 12 via an insulation material 16. An upper part 13 of the outer conductor 12 is halved into left and right parts in a state of opposing to each other by 180 degrees, the extension rods 14, 15 are respectively coupled to each other at an upper end part. In this case, the center conductor member 18 includes a coaxial feeder section 20 for a signal source, a balun 22 for an impedance conversion section, and a tubular filer 24 of a harmonic block filter section, and a tip 25 of the center conductor member 18 is connected to the extension rod 14 by a solder connection piece 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dipole antenna device that radiates radio waves from a power amplifier directly below an antenna via a coaxial feeder and an impedance converter, and more particularly to a phased antenna that emits radio signals as radiation-directed radio waves in any direction in space. The present invention relates to a dipole antenna that prevents harmonic interference when used in an array antenna.

A phased array antenna is usually configured by regularly mounting a plurality of dipole antennas on a reflector in a horizontal row or matrix. A phase shifter is electrically connected to each dipole antenna individually, and is connected to a signal source via a feed line of equal length for each phase shifter. Each phase shifter is individually connected by a microcomputer. By controlling the phase, the direction of radio wave emission to the space can be arbitrarily changed. Patent Document 1 discloses such a dipole antenna with a connector. The dipole antenna and the phase shifter can be attached and detached by connectors attached to the dipole antenna and the phase shifter, respectively.
Japanese Utility Model Publication No. 6-28811

For example, a conventional dipole antenna includes a T-shaped antenna base as shown in FIG. 4 and is configured to be connectable by mounting a housing or a coupling nut on the signal reduction side. The outer conductor 2 is a metal pipe called a so-called semi-rigid cable, and an overhanging rod 4 is welded and fixed to the upper end portion of the outer conductor. The The halved portions 3 are secured by welding or the like with extending rods 4 and 5 extending horizontally in the left and right outer directions so as to face each other by 180 degrees. On the other hand, an insulator 6 is inserted and disposed in the cylindrical hollow portion of the outer conductor 2, and there is a linear center conductor 8 that is inserted through the center of the insulator 6. One end of one overhanging rod 4 fixed to the outer conductor 2 is soldered and electrically connected at the tip of the center conductor 8. The dipole antenna having such a structure is adjusted so as to obtain a desired characteristic impedance Z ₀ depending on factors that slightly change depending on the dielectric constant of the insulator 6, the outer diameter, the outer diameter of the center conductor 8, and the like. The manufactured dipole antenna determines whether the product is good or bad by testing whether high-frequency characteristics such as voltage standing wave ratio (VSWR) are within a desired range.

  Since the joining state by soldering in the manufacturing process greatly affects the high frequency characteristics, it is desirable to completely infiltrate the solder into the fitting portion between the antenna and the inner hole of the housing or the like. If the penetration of the solder is insufficient and a gap is present, an inductance component is included, and the radio wave emitted from the antenna is attenuated. In addition, regarding the dimensional variation in the manufacturing process, the extension rod of the antenna should be flush with the distance from the lower surface to the upper surface of the reflector and the distance from the upper end surface of the housing to the same dimension. Desirably, if there is a deviation in the separation distance or variation in the separation distance, the reflected wave affects the traveling wave emitted upward from the antenna, and the radio wave of the emitted radio wave is spread.

  By the way, in recent years, with the power-up of the radio wave of the outgoing radio wave and the widening of the use frequency band, the influence of radio wave interference has arisen and legal regulations have been strengthened. This is so-called emission of an undesired radio signal in the emission of a desired radio signal, and in particular, it is required to prevent the emission of harmonic components of the desired frequency signal. Implementation of countermeasures for preventing emission of harmonic signals accompanying a desired radiation signal for a device using a conventional dipole antenna is a big problem in terms of space because it is necessary to cope between circuits from an amplifier to an antenna. On the other hand, signal power-up increases the generation level of harmonic signals to increase the influence of interference, and widening the frequency band used increases the chances of causing harmonic interference. To prevent radio interference, it is conceivable to install a blocking filter that removes harmonic components, which are unwanted signals, between the signal source, especially the amplifier circuit and the antenna, but the addition of a filter circuit increases the length of the equipment. This makes it difficult to renovate existing facilities and has a significant impact on economic costs.

  Therefore, the present invention has been proposed in order to eliminate the above-mentioned defects, and is a new and satisfying maintenance of a desired high-frequency characteristic by mounting a filter that blocks harmonic components in a compact and existing space. An object of the present invention is to provide an improved dipole antenna device.

  Another object of the present invention is based on the Radio Law regarding unnecessary radio wave radiation by reducing or eliminating radiation of unwanted harmonic signals from the antenna basically under the same structure as a conventional dipole antenna. An object of the present invention is to provide a dipole antenna device having a simplified structure including a balanced-unbalanced impedance converter that complies with regulations and obtains a desired characteristic impedance.

    According to the present invention, the hollow outer conductor whose upper part in the vertical direction is halved, and the extending rod that is integrally coupled to the upper half part of the hollow outer conductor and extends horizontally in the horizontal direction Comprising an antenna base comprising a member and a central conductor member arranged insulatively disposed inside the hollow outer conductor, wherein the central conductor member comprises a coaxial feeding part, an impedance conversion part and a filter part In particular, a dipole antenna device characterized in that the filter section is a tubular filter and functions as a low-pass filter (LPF) that blocks harmonic components of a desired signal to be radiated is disclosed. In addition, a dipole antenna device characterized in that a high-frequency blocking filter of a plurality of low-pass elements arranged in a hollow portion of a hollow outer conductor and an impedance converter that obtains a predetermined impedance characteristic are constituted by a central conductor member. The antenna device can be used as a phased array antenna that emits a radiation-directed radio wave beam in an arbitrary direction in space.

  In the present invention, since the low pass filter is housed together with the impedance converter in the hollow inside of the outer conductor of the dipole antenna, the interference signal of higher harmonics can be prevented while improving the space factor. In particular, the conventional antenna device can be easily repaired and replaced in response to the strengthening of legal regulations, and there is a practical effect such as no change in the transmission line from the power amplifier to the antenna device. That is, no extra space is required for installing the harmonic blocking filter, and the problem can be solved in the internal space of the antenna device, so that it is advantageous in terms of cost and can maintain the desired high-frequency performance.

  The present invention relates to a hollow outer conductor whose upper portion in the vertical direction is halved, and a protruding rod member integrally coupled to the upper half portion of the hollow outer conductor and extending horizontally in the horizontal direction. An antenna base having a central conductor member insulated and disposed inside the hollow outer conductor, wherein the central conductor member has a coaxial feeding portion, an impedance conversion portion, and a filter portion. This is a characteristic dipole antenna device. Specifically, a T-shaped antenna base, a connector housing provided on the outer periphery on the lower end side of the antenna base, and a radio wave output direction control phase shifter or extension cable connector provided on the outer periphery of the housing so as to be relatively rotatable. A dipole antenna device comprising a coupling nut that can be attached and detached, and having a harmonic blocking filter housed in an T-shaped antenna base together with an impedance converter balun. In particular, the filter unit is a tubular filter, and is a dipole antenna device that functions as a low-pass filter (LPF) that blocks harmonic components of a desired signal to be radiated.

Hereinafter, a dipole antenna device according to an embodiment of the present invention will be described with reference to FIG. The dipole antenna device shown in FIG. 1 is composed of a T-shaped antenna base, and a connector housing provided on the outer periphery of the lower end thereof, and a relatively rotatable device provided on the outer periphery of the dipole antenna device. The coupling nut to be omitted is omitted. That is, the antenna base 10 is made of a metal pipe and has a hollow outer conductor 12, horizontal extending rods 14 and 15 fixed to the upper end portion of the outer conductor 12, and an insulating material in the hollow portion of the outer conductor 12. 16 and a central conductor member 18 disposed via 16. The outer conductor 12 is halved to the left and right with the upper portion 13 facing 180 degrees, and overhanging rods 14 and 15 are joined together by welding at the respective upper ends, and are rods that extend horizontally on both sides. Is set to a half wavelength of the outgoing transmission signal frequency = λ / 2. The center conductor member 18 includes a coaxial power feeding portion 20 of a signal source having a power amplifier and a circulator, a balun 22 of an impedance conversion portion, and a tubular filter 24 of a harmonic blocking filter portion. 26 is connected to one of the overhanging rods 14. The balun 22 is set so as to have a desired characteristic impedance Z ₀ by changing factors such as the dielectric constant of the insulating material, the outer diameter and the length of the outer conductor and the central conductor.

  The high frequency blocking tubular filter according to the present invention forms a low-pass element by the lead inductance component L and the capacitance component C generated by the interaction of the outer conductor 12, the central conductor member 18, and the fluororesin insulating material 16 interposed therebetween. It is determined by factors such as the inner diameter of the hollow portion of the outer conductor 12, the outer diameter of the central conductor member 18, the dielectric constant ε of the insulating material 16, and the like. That is, L and C are determined by the number of stages of the thickness change portion of the central conductor member 18 and the mutual length to form a predetermined low-pass element, and high frequency unnecessary signals are blocked by the number of stages. The tubular filter condition can be determined in consideration of the return loss of a desired signal, the degree of blocking of an undesired harmonic signal, and the like. The dipole antenna device manufactured in this way is judged whether the product is good or bad by testing whether or not the blocking of the harmonic component is within a desired range.

  2 and 3 are high-frequency characteristics diagrams comparing the performance of the dipole antenna device according to the present invention shown in FIG. 1 and the conventional dipole antenna of FIG. That is, FIG. 2 is a high-frequency characteristic curve that compares return loss (reflection loss) with and without the low-pass filter (LPF), and clearly shows the difference with and without the low-pass filter (LPF) in the high-frequency mode. I understand that. On the other hand, FIG. 3 shows a characteristic curve at the output signal level to be radiated as a gain comparison. The desired signal (3 GHz band) in the vicinity of the marker 1 marked by Δ is the same level as that of the marker 2, The output levels of the second harmonic, the third harmonic of the marker 3, and the fourth and fifth harmonics of the markers 4 and 5 are clearly different, and an improvement of 30 to 40 dB is recognized depending on the presence or absence of LPF. Thus, when the LPF of the present invention is accommodated in the antenna base, the rejection rate of harmonic components is increased, which can greatly contribute to prevention of radio wave interference.

  The present invention provides a dipole antenna in which an LPF is accommodated in an antenna device in order to prevent unwanted radiation of harmonic components, and is applied as a phased array antenna of a radar device or the like, and has reliability to prevent radio wave interference. Provide enhanced products.

It is a fragmentary sectional perspective view of the dipole antenna device concerning the present invention. FIG. 2 is a high-frequency characteristic diagram of reflection loss due to the presence or absence of LPF in the antenna apparatus of FIG. 1. Similarly, it is a high-frequency characteristic diagram of gain comparison with and without LPF of the antenna device. It is a fragmentary sectional perspective view which shows the conventional dipole antenna.

Explanation of symbols

10; antenna base, 12; hollow outer conductor,
14, 15; projecting rod (member), 16; insulating material,
18; central conductor member; 20; coaxial power feeding part 22;
24; Tubular filter (filter part)
25; tip, 26; connecting solder

Claims (5)

A hollow outer conductor whose upper part in the vertical direction is halved, a protruding rod member that is integrally coupled to the upper part of the hollow outer conductor that is halved and extends horizontally in the horizontal direction, and the hollow An antenna base comprising a central conductor member insulated and disposed in a hollow interior of the outer conductor, wherein the central conductor member includes a coaxial feeding portion, an impedance conversion portion, and a harmonic blocking filter portion. A dipole antenna device. The dipole antenna device according to claim 1, wherein the harmonic rejection filter unit is a tubular filter, and functions as a low-pass filter that blocks harmonic components of a desired signal to be radiated. The dipole antenna device according to claim 2, wherein the impedance converter comprises a balun of a balanced-unbalanced converter that obtains predetermined impedance characteristics by the central conductor member. The high-frequency blocking filter section is configured as a multi-stage low-pass element by the central conductor member penetrating through the hollow inside of the hollow outer conductor, and is a phased array antenna that emits a radiation-directed radio wave beam in an arbitrary direction in space. The dipole antenna device according to claim 1, wherein the dipole antenna device is used. A T-shaped antenna base, a connector housing provided on the outer periphery on the lower end side of the antenna base, and a cup that is provided on the outer periphery of the housing so as to be relatively rotatable so that a radio wave emitting direction control phase shifter or an extension cable connector can be attached or detached. A dipole antenna comprising a ring nut, wherein the T-shaped antenna base includes a hollow outer conductor extending in a vertical direction, and a harmonic blocking filter is accommodated in the hollow portion of the outer conductor together with an impedance converter. apparatus.

Images