DE2062896A1 - Circuit for phase calculation for an antenna working with electronic beam swiveling - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Munich, 21.ΠΕ7. 1970

Berlin and Munich Wittelsbacherpl. 2

70/6828

Circuit for phase calculation for an antenna that works with electronic beam swiveling »·

The invention relates to a circuit for phase calculation for an antenna working with electronic beam swiveling, consisting of rows and columns There is individual radiators, whose current phase is in each case via a digital phase shifter, which is assigned by an Element memory is controlled, is set.

Phased antennas consist of many individual radiators, which are placed on a flat surface in usually orthogonal Rows and columns are arranged. The feed line is used for the electronic swiveling of the directional diagram Each individual radiator has a line section with an electronically adjustable electrical length, the so-called phase shifter, switched on. The phase shifters used in phase-controlled antennas, e.g. switching ferrites or Switching diodes are mostly of the digital type. With them, the detour that determines the phase position is not continuous, but rather only adjustable in steps. The detours are calculated in a phase calculator and must be done quickly that the operating speed of the entire system is not reduced.

In the case of radar use, the phase calculator works for the calculation the current phases of each individual radiator closely together with the central computer of the radar device.

The calculation and setting of the detours can in principle be carried out continuously using an analog computer and a digital computer and digital phase shifter.

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The analog phase shifters have a disadvantage the mean deviation of the phase from the nominal value is quite large. This causes the mean sidelobe level to rise too great a value.

In the case of a mixed (hybrid) version, a Analog computer connected to an analog-digital converter. Such a system works about as fast as the one previously described purely analog arithmetic unit. In contrast to the analog phase shifter, the digital phase shifter can be used Build with less scatter of the phase angle. This phase shifter can be either with an analog or digital phase calculator work together.

In a purely digital phase calculator, the electrical detour for each individual radiator is first calculated digitally. It is known to carry out this calculation individually at the location of each element. With the individual phase calculation the following calculation steps must be carried out:

1. Multiplication by a fixed value for ^ formation • the column phase.

2. Addition of the line contribution. The line contribution is determined in advance in a separate calculation value been.

3. A division by λ / λ_ αν and passing on the _{remainder of the division.}

The multiplication can be done as with the written multiplication in the decimal system to a sequence of additions and shifts. Accordingly, one can use the Build division on subtraction and shift.

Because with this purely digital solution, each element has its own arithmetic unit with individually programmed control possesses, however, the realization is extraordinarily difficult.

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agile.

The invention is based on the object of a device to adjust the phase shifter of a phased array antenna that allows rapid calculation of a Large number of phase values without burdening the central computer and with less effort than when setting up with an arithmetic unit per individual radiator. There should be a quick switchover from one beam direction to the next to be guaranteed. According to the invention, which relates to a circuit of the type mentioned above, This object is achieved in that, in order to calculate the vertical phase values, the assigned to the individual radiators Phase shifter within the individual lines a vertical arithmetic unit provision is made for a separate line for each line Horizontal arithmetic unit is provided that the horizontal phase values for each line for the vertical phase values are added and stored in the element memories and that the calculation of the electrical detour AL for the phase shifter of a single radiator, which is around a certain amount from its right and left neighbors and another certain amount from its upper one and lower neighbors, to a continued addition in adding units of the vertical arithmetic unit and the Horizontal arithmetic units is returned. Similar circuits can be used for the horizontal arithmetic units and use it for the element storage of each individual radiator. Furthermore, there is a large frequency range that can be used. Because the phase is not at the location of each individual radiator is composed in an individual arithmetic unit from column and line portion, arithmetic units can be save on.

The phase of the phase shifter may be frequency-dependent. In the case of a frequency-independent phase, the direction of the beam

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lungsmaximum frequency-dependent. As the electrical length of the phase shifter is frequency-independent, the deflection angle is also frequency-independent.

Purely for the way of working and the speed of work, it is advantageous if the vertical arithmetic unit and the horizontal reehen unit are in operation while the antenna is transmitting or receiving, with the • switched in the manner of a shift register Horizontal arithmetic units work at the same time.

The new ones are expediently stored in the element memories Phase values only after a switchover command to the Phase shifters effective.

Further details of the invention are based on an in a figure illustrated embodiment explained in more detail.

The figure shows a matrix-like arrangement in rows and columns of element memories ESP, their memory values can be entered into assigned phase shifter P for phase control of individual radiators S. The phase shifters P and the individual radiators S are only for two element stores ESP shown, but are provided for all element stores ESP. The element memories are set ESP via a vertical arithmetic unit VRY /, to which the control functions are fed from a radar control R, and each one horizontal arithmetic unit per antenna line. First, the vertical phase values of the individual lines are calculated with the vertical arithmetic unit VRV /. Then be with a horizontal arithmetic unit HRW for each line to the vertical phase values, the horizontal phase values are added and stored in the element stores ESP. here they are available for setting the digital phase shifter P. Disposal.

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The vertical phase values are calculated using the following equation:

V _n = nV - K ¹ P <P

It is

V = -r ^ · vertical phase increment

1 = electrical Y / eg between two vertically adjacent ones Antenna elements

λ = max. used wavelength

n = 1,, N number of additions == line number

N = number of lines

K ¹ = 1, 2, 3, .... paktor

λ = operating wavelength

V = vertical phase value after the η-th addition

φ.
F = -SiS Ratio of the phase difference cp _min at the lowest operating frequency f _m - _n to the phase difference φ at the current operating frequency f. For a phase shifter with a frequency-independent phase, i ¹ = !, for a phase shifter with a frequency-independent electrical length, P = or P = λ / λ ^ if λ = c / f and X _m = ^c / (c = speed of light)

As the above equation shows, the vertical phase values V are obtained by adding the vertical phase increment n times

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V = 1, Va calculated. The expression K «F is subtracted until V _n becomes smaller than F = \ / \ _m . The sizes V and]? are provided by the radar control.

In the vertical arithmetic unit VRW, the horizontal phase increment H-Iy ₁ A _1n and the normalized operation; frequency F calculates the difference HF; this operation is not required when using phase shifters with a frequency-independent phase.

The values V, H and possibly H-F are transmitted to the hearing? '- · zontal arithmetic unit HRW passed on. It is a measure; / tion provided, in which various impulses are generated ... which ensure that the processes in the vertical arithmetic unit proceed properly.

Each line is a separate Hörizontal arithmetic unit HRW v; seen that to V, the respective vertical phase value, m-iaal the horizontal phase increment H == Ij ₁₁ A addii according to the following equation *

H _m = V _n + mH - K "F <F
Where:

V = vertical phase value of the η-th line

H = Ij ₁ A _n . horizontal phase increment

1, = electrical path between two horizontally adjacent antenna elements

m = 1,2, ... M number of additions = columns number

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H - number of columns

K "= 1, 2, 3, .... factor

P «■ λ / λ normalized wavelength

H = phase value after the mth addition

The calculation of the phase values within a line is practically the same as with the vertical arithmetic unit VRW in front of you.

The horizontal phase increment H is added m times to the vertical phase value V, which changes from line to line by V = 1 _{γ / λ as described.} In addition, K ¹¹ F is subtracted when H> F. The values V, H and, if applicable, HF are supplied by the vertical arithmetic unit VRW. The input memory of all horizontal arithmetic units HRW together form a shift register. After the η-th shift cycle, the correct input variables are available in each shift memory of the HRW horizontal arithmetic unit. When using a phase shifter with a frequency-independent electrical length, the actual calculation process is carried out with two adders. In an adder the sum becomes

^H m1 = ^H m-1 ^{+ E}
and in the other adder the expression

^H m2 = ^H m-1 ⁺ ( ^H - ^P >
calculated.

If H <P, the expression H becomes . Inserted into the output memory via the selection grid. On the other hand, if H> P,

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H ρ is stored.

This process is caused by an overflow in the second Äddie ^ rer, which triggers corresponding control pulses for the selection gates in the clock control *

When using phase shifters with frequency-independent phase, only an arithmetic unit is used * Once H _-1 + H is greater than 1, an overflow occurs in the arithmetic unit, which corresponds to a reduction of the result H to the first This result is correct as long as F = I for the assumed phase shifter.

From the phase values calculated in the Horizohtal calculator HRV / the most significant bits are sent to the element memory ESP passed on. Here they are available for setting the phase shifters P.

The input stages of the element memory ESP of an antenna line together form a shift register. Hach the M-th Shift pulse is the correct phase value in the input memory of each element memory ESP. With a write-in impulse it is taken over into the Ausyangsspeieher.

The phasing is done by a digitally adjustable Realized phase shifter P, which is divided into sections between two different electrical Lengths or phases are switchable. The phase and length differences of the sections behave like 1: 2: 4: 8: 16 .. With 16 phase value-nn the phase shifter P has e.g. four sections (^ -Bit phase shifter).

The setting of the phase shifter P can in this example can be described by a four-digit binary number. The combination OLLO means for example

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O 180 ° bit in position O

J ₁ 90 ° bit in position

L 45 ° bit in position 45

0 22.5 ° bit in position Ό_

Set phase

Claims
figure

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Claims (1)

Pat entaasp.räcli e Circuit for phase range: for, one with electronic Beam-swiveling antenna that emerges from in Rows and columns arranged individual radiators, whose Stroniphaae each; via a digital phase shifter, which is controlled by an associated element memory, is set, thereby g ek e η η ζ e i ο h η e t, that snr calculation of the vertical Phase values of the den. Assigned to individual radiators (S) Phase shifter (P) within the individual lines a vertical -Hechenwerk (VRW) is provided that for each line a separate horizontal Reeiienw / Erk (HRW) is provided that for each line to the vertical phase values endLe horizontal Phase values are added and in the element stores (ESP) saved w / earth and that the calculation of the electrical Uni-way Ali for the phase shifter (P) of a single radiator (S), which is around a certain Amount (H) from its right and left neighbors and by another certain amount (V) from his upper and lower neighbors, distinguishes, on an addition, in adding units of the vertifcal arithmetic logic unit (VRV /) and the horizontal arithmetic unit (HET) is returned. 2, circuit according to claim!, Characterized in that that the vertical arithmetic unit (VRV /) and the horizontal arithmetic unit (HBW) are in operation while the antenna transmits or receives, and that the services referred to in Art of a shift register switched horizontal arithmetic (HR ', /) work at the same time. 3. A circuit according to claim 1 or 2, dad u rch characterized in that the phase values stored in the Eleraentspeicher (ESP) only become effective after a switch command on the phase shifter (P), VPA 9/433/105 -If-, 209829 / 008S 4. Circuit according to one of the preceding claims, d adurch marked that the digital Phase shifter (P) for any frequency response are designed. 5. Circuit according to one of claims 1 to 3, characterized gekennz e i chnet that the phase setting of the phase shifter is frequency-independent and therefore the Frequency parameter F is always equal to one, so that half of the adders are omitted. VPA 9/433/105 209829/0085 Blank page