JPS5853235A - Receiving system of maximum energy - Google Patents

Abstract

PURPOSE:To obtain a phasing eliminating circuit which is best suited to various molding/demodulating systems, by converting with high efficiency the signal received through a current antenna and a magnetic current antenna into the 3rd receiving wave. CONSTITUTION:The outputs given through a loop antenna and a half-wave length dipole antenna are properly synthesized by a 180 deg. hybrid circuit 20, a 90 deg. circuit, etc. Thus a nondirectional magnetic current antenna output eH is obtained at a terminal P. At the same time, a nondirectional current antenna output eE is obtained at a terminal Q. These outputs eH and eE are converted into the 3rd receiving wave via a phase control circuit 18 and the circuit 20 to be supplied to a signal receiver 22. A phase control is given to the circuit 18 and a minute phase shifter 19 so that the received signal output power of the receiver 22 is set the maximum level.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reception method that reduces the effects of fading in mobile communications.

In mobile communications, radio waves often propagate as multiple waves while being reflected and refracted by buildings, trees, etc., and complex standing waves are formed around the reception point. Therefore, when the mode of the standing wave changes due to changes in the surroundings, or when the reception point moves and crosses the standing wave, the reception level fluctuates greatly. In particular, when the reception point is near a node of a standing wave, the reception level becomes extremely low. Such fluctuations are called fading, and are an important problem to overcome in mobile communications.

An energy density reception method is known as one method for overcoming fading. This is because when there is a standing wave, where the electric field component E of the radio wave becomes a node, the magnetic field component H becomes an antinode, so if E and T are received at the same time, fluctuations due to fading can be eliminated. This means that it can be reduced. This idea was suggested by J.R., Pierce and E.N., G11bert.
(E, N, G11bert, ”Ene
rgy reception for mobile r
adio, ” Be1l 5yst, Tech
, Journal, XLIV.

1) I), 1779-1803.0ctober 19
65°).

and W, C, -Y, Lee' (W, C, -Y,
Lee, “Theoretical and expe.
rimental 5tudy of the pro
parties of the signal from
an energy density mobile
radio antenna, ”TEEE Tra
ns, on vehicle technology
gy, vol, VT-16+pp, 25-32.
Its effects have been studied by 0ctober 1.967, ).

The receiving system tested by Lee is shown in Figures 1 and 2. FIG. 1 shows the antenna section, where (a) is the antenna and (b) is the separation circuit. In the figure, 1 is a grounding plate, 2 and 3 are half-wavelength loops, 4, 5.6 are 180° hybrids, and 7 is a matching load. Regarding the hybrid circuit, the in-phase output terminal is indicated by T, and the negative-phase output terminal is indicated by O. The separation circuit (b) separates and outputs the electromagnetic field components (Ex, Hx, Hy) of the space where the antenna is installed. Each component is amplified and detected by a receiving circuit shown in FIG. 8 is a receiver, 9 is a square law detector, and 10 is a combiner. Since the square-law detection outputs are combined as the detection output in this way, there is a drawback that phase information cannot be extracted and the applicable modulation/demodulation methods are limited. Another disadvantage is that it requires three series of receivers and is not suitable for miniaturization of mobile communication devices.

The present invention converts two received waves received by a current antenna provided inside a three-dimensional space with a maximum linear distance of less than half a wavelength into a third received wave with the carrier wave as it is, and It is characterized by controlling so that the power of the third received wave is maximized, and its purpose is to efficiently convert the power received by the current antenna and magnetic current antenna into the third received wave and overcome fading. . When the three-dimensional space is spherical, the diameter is less than half a wavelength, and when the three-dimensional space is a rectangular parallelepiped, the diagonal is less than half a wavelength. When the three-dimensional space is larger than half a wavelength, it is not suitable as a small and mobile antenna.

An embodiment of the present invention is divided into an antenna section and a receiving section, which are shown in FIGS. 3 and 4, respectively. FIG. 3(a) shows the antenna, where 1 and 12 are half-wavelength loop antennas that are sufficiently small compared to the wavelength, and 13 is a dipole antenna. D
I I 021 Pl + F21 G is an antenna terminal. If the sensitivity to the magnetic field of 11 and 12 is insufficient, the loop may be made into a coil shape. Further, slot antennas provided on the cylindrical body of the receiving device may be used instead of 11 and 12. FIG. 3(1)) shows a magnetic current antenna synthesis circuit. 14, 15 are 180' hybrid, ]6 is 90° hybrid, 17 is matched load,
P and Q are output terminals. 14 and 15 negative phase output terminal 0
At 4 and 05, received waves proportional to the magnetic field [1]

It is also clear that the omnidirectional current antenna output eE is obtained at the Q terminal. Note that in the above description, it is assumed that each antenna and the transmission line are matched, and the matching circuit is omitted.

In FIG. 4, the third received wave eT is obtained by phase synthesis from the eF and the light obtained as described above. 18 is a control phase shifter, 19 is a micro phase shifter for control, 20 is 180
° Vibe IJ Sodo, 21 is matching load, 22 is receiver,
24 is a control small signal generator, 25 is a square law detector, 26 is a correlator, and 27 is a control circuit.

If the phase shift amounts of J8 and 19 are φ and Δφ, respectively, then 20
The in-phase composite output eT is as follows: eT = AE 5in (ω(1) + AH3in
(ω(1 + θ - φ - Δφ Roux (1). AF, and A
H is the amplitude of eE and eH, respectively, and θ is eH with respect to eE.
is the phase difference. If the minute phase shift amount Δφ is ignored, eT = AT sin (ωct ten φ)
−(
It becomes 2+. However, . FIG. 5 shows the relationship between AT and (θ-φ) when AE and AH are used as parameters. As can be seen from this figure, except for the special case of AE-0 or AH-0, AT is maximum when θ-φ-〇. Therefore, φ−
If phase control is performed so that θ is achieved, the maximum energy can be received. The state of such control is shown in a vector diagram in FIG.

Note that when receiving only one wave instead of multiple waves, θ
coincides with the angle of arrival and becomes AE-AH. therefore,
The phase control of φ--θ corresponds to adaptive control so that the direction of maximum directivity caused by phase combination of the current antenna and the magnetic current antenna coincides with the direction of arrival.

Phase control is performed using the circuit shown in FIG. 4 as follows.

In this circuit, first, 19
Add a minute phase shift modulation of Δφ using . The fr should be several times the fading pinch or more. When this phase modulation of Δφ is performed, a pulsation of fr is observed in the square-law detection output of B when φ←θ. Therefore, the frequency component of fr is extracted using 26 correlators. It is related to the control error of the extracted fr acid component φ and is proportional to −5in (φ−θ). Therefore, if φ is controlled so as to give negative feedback to this, it is possible to control φ to become φ−θ.

Now, in the method described above, phase synthesis is performed in order to perform maximum energy reception, but almost the same effect can be obtained by selecting eE and eH by switching. An example is shown in FIG. In this method, that switching circuit is used as a conversion circuit. Switching of the switching circuit is controlled while monitoring the output level of the receiver 20 by a control circuit 29. The switching algorithm can be determined relatively easily by considering the physical fact that eE and eH reflect the energy density of the electric field and magnetic field near the antenna. For example, if a standing wave is generated due to two-wave interference as shown in Figure 8(a), switch the switch when the power of the received wave whose level is being monitored drops by 3 dB from the extreme value. , it is possible to receive maximum energy with a level fluctuation of about 3 dB. The state of switching is shown in FIG. 8 (1)). For comparison, the receiving system using phase synthesis is shown in FIG. 8(C). In Fig. 8, the horizontal axis shows distance, Fig. 8 (1)) shows the directivity of the current antenna (E) and magnetic current antenna (H), and Fig. 8 (C) shows the directivity of the composite wave. show.

In addition to the above-described loop antenna, half-loop antenna, and slot antenna, examples of magnetic current antennas include, for example, a shielded loop antenna shown in FIG. 9(a), and a shielded loop antenna shown in FIG. 9(b). A short-circuit loop antenna and an antenna combining two single-wavelength antennas shown in FIG. 9(C) are possible. In these figures, 30 is the ground, 32 is the inner conductor, 34 is the outer conductor, 40 is the short circuit point, 50 is the shield plate, 52 is the 1800 hybrid, and the 9th
It is assumed that the length Ll in Figure (C) is within half a wavelength, and L2 is one wavelength.

As described above, according to the present invention, it is possible to utilize the electric field energy and magnetic field energy of radio waves to the fullest with a single receiver, and to overcome fading. Furthermore, since the signal is converted into the third received wave in the carrier band, it can be applied to any modulation/demodulation method. Furthermore, since the control circuit operates in the IP or base band, it is easy to integrate it into an IC. Therefore, fading can be overcome with a simple equipment configuration, which is particularly useful for small portable receivers.

[Brief explanation of the drawing]

Figures 1 (a) and (1)) and Figure 2 are block diagrams of conventional energy density reception systems, and Figure 3 (a) and (1).
) and FIG. 4 are block diagrams of a phase synthesis method according to an embodiment of the present invention, FIGS. 5(a) to (C) and FIG. 6 are explanatory diagrams of phase synthesis according to the present invention, and FIG. FIGS. 8(a) to 8(C) are operation explanatory diagrams in the case of two-wave interference, and FIGS. 9(a) to 9(C) show various embodiments of the magnetic current antenna. 1... Ground plate, 2, 3... Half loop antenna, 4.5.6... 180° hybrid, 7... Matched load, 8-1.8-2.8-3. ...Receiver, 9
-1.9-2.9-3... Square law detector, 10... Combiner, 11, 12... Half-loop antenna, which is sufficiently small compared to the wavelength, 13... Dipole antenna, 14 , , 15...180°hybrid, 16...
90° hybrid, 17-1, 17-2, ]? -3...Matched load,
18.19... Phase shifter, 20... 1800 hybrid, 21... Matching load, 22... Receiver, 23...
- Detector, 24... 11 oscillator, 25... Square law detector, 26... Correlator, 27... Phase shifter control circuit, 28... Switching circuit, 29... Switching control circuit. Patent Applicant Nippon Telegraph and Telephone Public Corporation Patent Application Agent Megumi Yamamoto - Paper 3 Figure rb) e8. eE Tail 5 Eye Figure 8 Good Ding J!゛Fig.cb) Fig.CC)L. “'1 Yo-yo, H, ii,' 50

Claims (1)

[Claims] An omnidirectional current antenna and an omnidirectional magnetic current antenna are installed inside a three-dimensional space with a maximum straight distance of half a wavelength or less, and a third antenna is used by phase synthesis and switching, or a combination thereof, of the received waves from each antenna before detection. A maximum energy receiving system characterized by having a conversion circuit that converts into a received wave and a control circuit that controls the conversion circuit so that the output of the conversion circuit is maximized.