JPS6031295Y2 - small antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a small antenna used to receive signals such as radio (FM) or television VHF radio waves.

In this type of antenna, it is said that it is desirable that the total length of the dipole antenna be 2/2 (λ: wavelength).

However, when such a value is set, the lengthwise dimension of the dipole element becomes significantly large, which has the disadvantage that handling such as transportation and installation is very inconvenient.

In order to shorten this, it is conceivable to connect a reactance element in series with the dipole element, but this has the problem of narrowing the reception bandwidth.

Therefore, the present invention provides a small antenna that prevents narrowing of the band even if the longitudinal dimension of the dipole element is shortened, exhibits wideband characteristics, and has good characteristics such as gain and directivity. This is what I am trying to do.

The drawings showing the embodiments of the present application will be described below.

Reference numerals 1 and 2 each indicate two sets of dipole antennas, which are arranged parallel to one another with respect to the direction of arrow 18 shown as the radio wave reception direction.

In the above dipole antenna 1, 3, 4° 3', 4
' indicates a dipole element formed of a conductive material, and the two elements 3, 3' and 4, 4' located on the left and right, respectively, are spaced at an appropriate distance d, that is, the Q at the time of resonance of the dipole antenna is lowered, and broadband characteristics are achieved. almost parallel to each other with a distance d between them (for example, so that the tip side is slightly narrower)
are arranged and each of these dipole elements is indicated by an arrow 18.
It is inclined at a relatively small arbitrary angle θ toward the 18 direction side with respect to the direction orthogonal to the direction.

Furthermore, each of the dipole elements is formed to have a short longitudinal dimension so that the total length of the dipole antenna 1 is shorter than the total length of a generally known half-wavelength dipole antenna.

5.5 are two dipole elements 3 located on the left and right, respectively,
Two coils (usually called loading fills) 6, each having the same value by electrically connecting the bases of 3' and 4, 4', respectively, are actance elements.
It is configured so that it can be divided into 6 parts.

Incidentally, since the dipole antenna 2 has the same or equivalent configuration as that of the dipole antenna 1, the same reference numerals as those for the dipole antenna 1 are given, and redundant explanation will be omitted.

Next, 10 is the intermediate point 5', 5' of the reactance elements 5, 5 in the dipole antenna 1 and the balanced-unbalanced converter 8.
11 is a feeder line connecting intermediate points 5', 5' of the reactance elements 5, 5 in the dipole antenna 2 and the balanced-unbalanced converter 9, which are configured as a balanced line. and the respective line lengths are usually the same.

Note that the one balanced line 10 constitutes a commonly known phase inversion circuit.

Further, as is well known, the converters 8 and 9 are configured to match impedance and convert a balanced current into an unbalanced current.

Reference numeral 12 denotes a well-known combiner, which is configured to combine the signals inputted from the converters 8 and 9, and output the combined signal from an output terminal 13.

Reference numeral 14 denotes a feeder line connecting the converter 8 and the combiner 12, and 15 a feeder line connecting the converter 9 and the combiner 12, which are configured as a non-finger-shaped line.

Each distance (electrical length) of these feeder lines 14.15 '1
? '2 satisfies the relationship that the difference between these is 0.125 people, and uses the commonly known phase difference feeding method to provide dipole antennas 1 and 2 for radio waves coming from the direction of arrow 19. so that the respective received signals from the dipole antennas 1 and 2 cancel each other out, and so that the respective received signals from the dipole antennas 1 and 2 are synthesized without being canceled against radio waves coming from the direction of arrow 18. It is set.

That is, antenna radiation is set to be maximum in the 18th direction and minimum in the 19th direction.

Note that each of the above antennas is set to a value similar to the normal method.

L=0.34λ, D=0.125 people, θ=15°,
d = 0.014λ, value of coil 6 = 0.7μH (receiving frequency 76-90MH2), If = 0.085
People, 12 = 0.21 people.

(In: Wavelength) In the above configuration, the reactance element 5 is provided in order to shorten the overall length of the antenna, so even if the reception bandwidth may become narrow, each dipole The antennas 1 and 2 include two dipoles 3, 3' and 4, which are spaced apart from each other in the radio wave reception direction on the left and right sides, respectively.
Since the dipole antennas 1 and 4 are arranged in parallel, the electrical characteristics of each dipole antenna 1 and 2 are as follows: Equivalent to the electrical characteristics of a dipole antenna, the Q of each of the dipole antennas 1 and 2 during resonance decreases, and exhibits broadband characteristics.

In addition, since the two sets of dipole antennas 1 and 2 are arranged one after the other in the direction of the arrow 18 and are connected as described above, the output terminal 1 is connected to the signal from the radio signal direction.
The gain appearing in antenna 3 is larger than that in the case of dipole antenna 1 or 2 alone, and interference waves from the direction opposite to radio wave reception can be largely eliminated.

This point will be further explained based on the various types of antennas shown as examples above.

(1) With respect to the signal from the radio wave receiving direction, if the phase at the point of dipole antenna 1 is taken as a reference, the signal received by dipole antenna 1 will be 0,
Due to the 5 person phase lag and the 0.085 person phase lag in the feeder line 14, it reaches the combiner 12 with a total of 0.585 person phase lag.

Furthermore, the signal received by the dipole antenna 2 has a total phase delay of 0.335 A due to the phase delay of 0 and 125 between the dipole antennas 1°2 and the phase delay of 0 and 21 in the feeder line 15. Synthesizer 1
It will arrive on 2nd.

Therefore, both signals reaching the combiner 12 are 0.585-0.
According to the calculation of 335=0.25, the synthetic leather is formed with a phase difference of 0.25λ.

As a result, a larger output signal can be obtained at the output terminal 13 than in the case of the dipole antenna 1 or 2 alone.

(2) With respect to the signal from the opposite radio wave reception direction, if the phase at the point of dipole antenna 2 is taken as the reference, the signal received by dipole antenna 1 will be
There is a total phase delay of 0.71 people due to the phase delay of 0.125 people between the two, the phase delay of 0.5 people in the phase inversion circuit, and the phase delay of 0.085 people in the feeder line 14. The synthesizer 12 is reached.

Also, the signal is received by the dipole antenna 2 and is sent to the feeder line 15.
Synthesizer 1 with only 0,21 phase delays in
It will arrive on 2nd.

Therefore, both signals reaching the combiner 12 are 0.71-0.2
According to the calculation of 1=0.5, the leather is synthesized with a phase difference (opposite phase) of 0.5λ.

That is, both signals cancel each other out. As a result, signals from the opposite direction of radio wave reception can be excluded.

Furthermore, the antenna has very good directivity in the direction of arrow 18.

Note that the above-mentioned phase inversion circuit attached to the dipole antenna 1 side may be configured to the other dipole antenna 2 side.

Further, the feeder lines 14 and 15 do not necessarily have to be non-finger-shaped lines, but may also be balanced lines.

In this case, the converters 8 and 9 are of course unnecessary.

Further, the inclination angle θ of each dipole element may be set to 0 degrees, that is, each of the above-mentioned elements may be orthogonal to the direction of arrow 18.

As described above, in this invention, the two sets of dipole antennas 1 and 2 include two dipole elements 3, 3' and 4, 4' arranged approximately parallel to each other on the left and right sides, respectively. Since the dipole element is connected via the actance element 5 on the base side of the dipole element, even if each of the above dipole elements is formed short or small by the dipole element of the dipole antenna whose total length is λ/2, the gain will be less than the total length. It has the advantage of being able to obtain a sufficient gain similar to the input/2 dipole antenna, and as a result, it has the advantage of being able to be made compact, that is, the longitudinal dimension of the dipole element can be shortened for ease of transportation.

Moreover, even if the length of the dipole element is shortened in this way, the broadband characteristics will be poor because each dipole element is arranged in two horizontal parallels at an appropriate interval as described above. It also has the effect of being able to receive high-quality received signals over a wide band.

Furthermore, in the present invention, two sets of such dipole antennas 1.2 are arranged one behind the other in the radio wave receiving direction 18, and their electrical coupling is in the radio wave receiving direction 18, as is clear from the above description. Since the signals from the opposite radio wave receiving direction 19 are synthesized and the coupling distance of the coupling feeder line is set so that the signals from the opposite radio wave receiving direction 19 cancel each other out, the gain is doubled and the directivity is good. As a result, the small antenna with the configuration of the present invention has a wide reception performance, high gain, and good directivity even though the longitudinal shape of the dipole element is small, as described above. It has some practical advantages.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a plan view showing the relationship between each member of the antenna. 1.2...Dipole antenna, 3t 3'
t4.4'...Dipole element, 5,5...
...Reactance element, 12...Synthesizer, 1
8... Radio wave reception direction, 19... Counter radio wave reception direction.

Claims (1)

[Scope of utility model registration request] Two sets of dipole antennas are arranged one behind the other in the radio wave receiving direction, and each dipole antenna is equipped with two dipole elements on each side of the left and right sides, and the two dipole elements on the left side are arranged in an appropriate manner with respect to each other. The two dipole elements on the right side are also arranged approximately parallel to each other with an appropriate interval apart, and the base beams of those dipole elements are The reactance elements in each dipole antenna are connected to each other via an actance element, and each intermediate portion of the reactance element in each dipole antenna is connected to a combiner via a feed line, and the distance between the front and rear dipole antennas is The relationship between the electrical length of the feed line connected from the combiner to the dipole antenna in the previous stage and the electrical length of the feed line connected from the combiner to the dipole antenna in the latter stage is that for radio waves arriving from the radio wave receiving direction, , the reception signal received by the dipole antenna in the previous stage and arriving at the combiner via the feed line is combined with the reception signal received by the dipole antenna in the latter stage and arriving at the combiner through the feed line, and For radio waves arriving from A small antenna characterized in that the antennas are set in such a relationship that they cancel each other out.