GB2176660A

GB2176660A - Aerial arrangement for electronic proximity fuses or spacing fuses

Info

Publication number: GB2176660A
Application number: GB08512476A
Authority: GB
Inventors: Klaus Schricker
Original assignee: Licentia Patent Verwaltungs GmbH
Current assignee: Licentia Patent Verwaltungs GmbH
Priority date: 1984-05-29
Filing date: 1985-05-16
Publication date: 1986-12-31
Also published as: SE8503156L; DE3420046C2; DK231485A; SE8503156D0; SE463001B; GB2176660B; DE3420046A1

Abstract

For rough use in electronic proximity fuses or spacing fuses operating in the microwave range, wideband matching to the characteristic impedance of the system with small standing wave ratio is realised in simple manner by means of an aerial arrangement with two aerial units 8,9 electromagnetically coupled by dielectric 7. The one aerial unit 8 is a monopole coupled to the centre conductor 4 of an asymmetric feed. The other aerial unit 9 is a dipole which is constrainedly symmetrised through a conductive connection of its foot ends with the return conductor 5 of the feeding-in line. In a preferred embodiment (Fig. 3), the two aerial units are strip lines 13, 14 on respective facer of a dielectric substrate 15. <IMAGE>

Description

SPECIFICATION Aerial arrangement for electronic proximity fuses or spacing fuses.

The invention concerns an aerial arrangement according to the cissifying clause of the patent claim 1.

The invention is based on the taskof realising an aerial arrangement in the microwave range, which is suitable for the rough use in electronic proximity fuses and spacing fuses and is manufacturable at favourable cost as mass-produced article. In particular, it shall serve for the transmitting and/or receiving as well as also as symmetrising equipment for projectile aerials. This problem is solved in an arrangement according to the species by the characterising features of the claim 1.

Further advantageous refinements and developments are contained in the subclaims.

The advantages attained by the invention lie in that a simple symmetrising equipment, free of direct current path, of small overall volume is realisable by means of such a coupled aerial arrangement.

In particular, a wideband matching to the characteristic impedance of the system with small standing wave ratio is very easily possible with simultaneous saving of a blocking capacitor.

Furthermore, symmetrical radiation diagrams can be realised by this arrangement also with input impedances lying in the proximity of 50 ohms.

The invention shall be explained more closely in the following by an example of embodiment.

In the drawing belonging to the examples of embodiment, there show: Figure I basic principle of the aerial arrangement, Figure 2 monopole aerial capacitively coupled with a dipole aerial, Figure 3 strip line construction of the aerial arrangement for electronic proximity fuses and spacing fuses, (a) front side of carrier substrate (TV), (b) side elevation and (c) rear side of carrier substrate (TR).

The basic principle of the aerial arrangement 1 is illustrated in Fig. 1. For the asymmetrical feeding of a-for example-aerial unit 3, which is symmetrical about earth, by means of a - for example -- co-axial line 4, a further neighbouring aerial unit 2, which is electro-magnetically more than critically coupled through the medium K with the aerial unit 3 symmetrical about earth, is employed in advantageous manner. For symmetrisation of the aerial unit 3, the foot 6 of the aerial unit 3 is preferably conductively connected with the return conductor 5, lying at earth potential, of the co-axial cable.

In accordance with the given characteristic impedance of the system, in the case of the example the characteristic impedance of the co-axial cable 4, the coupling K between the aerial units 2 and 3 is to be so chosen by way of the given impedance values, which determine the input impedance of the arrangement, of the individual aerial units 2 and 3 that the co-axial line 4 is terminated as free from reflection as possible within a given bandwidth in the operating wavelength range.

The aerial units 2 and 3 are therefore preferably tuned to the same operating wavelengths. As an aid in dimensioning, the aerial arrangement according to the invention can in advantageous manner be described to a good approximation, confirmed in practice, electrically by a series resonant circuit (realised substantially by the aerial unit 2) coupled with a parallel circuit (realised by the other aerial unit 3). From the circuit data and the electromagnetic coupling, the input impedance values of the arrangement then let themselves be determined in correspondence with the calculation of - for example -- multi-circuit filters.To increase the relative bandwidth, within as reflection-freeline termination as possible, the coupling is preferably to be chosen to be more than critical and as parallel as possible a position of the aerial conductors of the aerial units each relative to the other as well as a smallest possible aerial foot spacing for a given coupling are to be aimed at.

Fig. 2 in advantageous manner shows a monopole aerial 8, which serves for the asymmetrical feeding-in of a wave conducted on a for example -- co-axial line and which is capacitively coupled by way of the dielectric 7 with a dipole aerial 5. In advantageous manner, a capacitor is saved by the feeding-in free of direct current path.

The input impedance of the aerial arrangement is composed of the effective impedances, dependent on the coupling K, of the monopole aerial and the dipole aerial.

Through encapsulation of this aerial arrangement, an acceleration-resistant small construction is easily realisable in terms of production technique.

The dielectric properties of the casting material and the position or arrangement of the aerials 8 and 9 each relative to the other, particularly the mutual spacing, determine the electromagnetic coupling and thereby also the input impedance behaviour of the aerial arrangement 1. For symmetrisation of the dipole aerial 9, its foot ends 1 lea and 1 1b are conductively connected each with the other and in advantageous manner directly with the return conductor 5 of the co-axial line 4 by way of a conductor portion 12.

Fig. 3 shows a special advantageous embodiment, operating for example in the gigahertz range, for the use in electronic proximity fuses or spacing fuses. There, the limbs of the dipole aerial and of the monopole aerial are bent away from the aerial foot at a given spacing d dependent on the shape of the fuse housing. The limbs T1 and T2 of the dipole aerial 14 in this case lie rotationally symmetrical to the fuse housing in a common plane.

Preferably, the aerials are constructed in strip line technique. For example, the strip conductor of the monopole aerial 13 is mounted on the front side TV of a delectric carrier substrate 15 and the strip conductor of the dipole aerial 14 on the planar parallel rear side TR of the carrier substrate.

The asymmetrical feeding-in takes place preferably by way of a conductor strip L1, which is narrow in comparison with the monopole limb and lies parallelly and near to the fuse housing axis A.

Preferably, the foot ends 11 of the dipole aerial 14 are conductively connected each with the other and by way of a conductor strip L2 with the return conductor 5, lying at earth potential, of the feeding-in line 4.

This "constrained symmetrisation" of the dipole aerial 14 leads in advantageous manner to a loop formation of the input impedance Ztn of the aerial arrangement. In practice, it proved to be an advantage to choose appropriately large conductor spacings, i.e. the greatest possible spacing of the angled limbs of the dipole aerial 14, in order hereby to be able to realise input impedances Z in the neighbourhood of 50 ohms.

For wideband applications, it is furthermore of advantage, particularly when the input impedance shall remain substantially constant and the standing wave ratio less than 1.5 within more than 10% of relative bandwidth, to choose the operating wavelength of the dipole aerial and of the monopole aerial to be equal, i.e. to choose the electrical lengths of the limbs to be 44 as well as to design the capacitive coupling between monopole aerial and dipole aerial to be more than critical, thus more than 50%. For the attainment of a substantially symmetrical radiation diagram horizontally as well as also vertically - rela- tive to the longitudinal axis A of the fuse housing, the aerial arrangement according to Fig. 3 is to be integrated in the housing.In this case, in advantageous manner, the spacing of the aerial feet 10 and 11 of the monopole aerial and dipole aerial is to be kept as small as possible and the limb T3 of the monopole aerial is to be arranged in such a manner that the plane spanned by the monopole limb lies parallelly to the plane spanned by both the limbs T1 and T2 of the dipole aerial.

The spacing of the aerial feet 10 and 11 then corresponds to the thickness do of the dielectric which substantially causes the capacitive coupling.

A further advantage of this aerial arrangement 1, built up symmetrically relative to the fuse housing axis A, lies in the attainment of a radiation diagram, independent of projectile, preferably through the "constrainedly symmetrised" aerial foot 11, which lies in the fuse housing axis A, of the dipole aerial 14. The further incorporation of additional transformation elements and filter elements is possible in advantageous manner between aerial foot and point of the feeding-in of the line-conducted wave, for example in the form of discrete components or also through appropriate dimensioning, known from the line theory, of the conductor strip L1.

A fine tuning of the operational frequency to the target frequency, of the input impedance Z:n to the characteristic impedance of the system and of the capacitive coupling between monopole aerial and dipole aerial is possible in advantageous manner through thinning-out or shortening of the conductor strips of the aerials. Just so, the radiated power of the dipole aerial 14 is possible for example through increasing the spacing of the angled limbs or thinning-out of the conductor strip L2.

The position of the locus of polar frequency response of the input impedance Ztn of the aerial arrangement (for example in the Smith diagram representation) lets itself be varied through appropriate alteration of the dimensioning (length, width) and of the mutual spacing of the conductor strips of the aerials and thereby be matched to given target impedance values.

Claims

1. Aerial arrangement for the use in projectiles, particularly for electric proximity fuses or spacing fuses operating in the microwave range, characterised thereby, that the aerial arrangement (1) contains at least two aerial units (2, 3) each electromagnetically coupled with the other through a coupling medium, that the one aerial unit (2) serves for one thing for the asymmetrical feeding-in of an electromagnetic wave conducted on a line (4) and for the other together with the other aerial unit (3) for the radiation and/or reception of electromagnetic waves and that the return conductor (5) of the line (4) is for the symmetrisation of the other aerial unit (3) connected with the foot ends of the foot (6) of the other aerial unit (3).

2. Aerial arrangement according to claim 1, characterised thereby, that the aerial conductors of the aerial units (2, 3) each lie parallelly to the other andthat the aerial units (2, 3) are separated by a dielectric (7) in accordance with the electromagnetic coupling.

3. Aerial arrangement according to one of the claims 1 to 2, characterised thereby, that the aerial units (2, 3) are each substantially capacitively coupled with the other.

4. Aerial arrangement according to one of the claims 1 to 3, characterised thereby, that the aerial units (2, 3) are each more than critically coupled with the other.

5. Aerial arrangement according to one of the claims 1 to 4, characterised thereby, that the one aerial unit is constructed in the form of a monopole aerial (8) and the other aerial unit (3) in the form of a dipole aerial (9), that the monopole aerial (8) is capacitively coupled through a dielectric (7) with the dipole aerial (9) and that the foot (10) of the monopole aerial (8) serves for the feeding-in of the lineconducted electromagnetic wave (W) and the foot ends (1 lea, 1 1b) of the dipole aerial (9) are conductively connected through a conductor portion (12) each with the other and with the return conductor (5) of the line (4).

6. Aerial arrangement according to claim 5, characterised thereby, that the limb of the monopole aerial (8) and the two dipole limbs of the dipole aerial (9) are bent away at a predetermined spacing (d) from the associated aerial feet (10, 11).

7. Aerial arrangement according to one of the claims 5 to 6, characterised thereby, that the aerial arrangements are built up in conductor plate technique or in strip line technique, that the monopole aerial (13) is applied in the form of a conducting layer on the front side of a dielectric carrier substrate (15) and the dipole aerial (14) is applied in the form of a conducting layer on the planar parallel rear side of the carrier substrate (15) and that the thickness (do) and the dielectric properties of the carrier substrate material (15) are appropriately chosen in accordance with the electromagnetic coupling between monopole aerial (13) and dipole (14).

8. Aerial arrangement according to one of the claims 6 to 7, characterised thereby, that the angled parts (T1, T2) of the dipole aerial (14) are each arranged rotationally symmetrically to the other relative to the longitudinal axis (A) of a projectile on the carrier substrate rear side (TR) and the one angled limb (T3) of the monopole aerial (13) is arranged on the carrier substrate front side (TV) and lying directly opposite one of the angled parts (T1 or T2) of the dipole aerial, that the feeding-in (E) of the electromagnetic wave takes place asymmetrically through a conductor strip (L1), which is narrow compared with the angled monopole limb and lies near and parallelly to the longitudinal projectile axis (A), and that the dipole aerial foot (11) is connected through a wide conductor strip (L2), which lies near and parallelly to the longitudinal projectile axis, with the return conductor (5) of the feed-in line (4).

9. Aerial arrangement according to one of the claims 1 to 8, characterised thereby, that the electrical length of the limbs of the limbs of the dipole aerial (14) and that of the monopole aerial (13) are chosen to be A/4 long in accordance with the operating wavelength A.

10. Aerial arrangement according to one of the claims 1 to 9, characterised thereby, that the spacing of the aerial feet (10, 11) of the monopole aerial and the dipole aerial is a minimum and that the limb of the monopole aerial (T3) lies parallelly to both the limbs of the dipole aerial (14).

11. Aerial arrangement according to one of the claims 1 to 10, characterised thereby, that transformation elements and filter elements are effective between aerial foot (10) of the one aerial unit (2) or of the monopole aerial (13) and the feed-in location (E) of the lineconducted wave (W).