SU1474563A1 - Multi-channel device for measuring amplitude-phase field distortions of phased array - Google Patents

Abstract

The invention relates to antenna measurements. The purpose of the invention is to improve the accuracy of measurement of the amplitude and phase distribution of a phased antenna array (PAR). The device contains a microwave generator 1, a power amplifier 2, a scanner carriage 4 on which a probe collimator 5 and a microwave 6 are placed, as well as a mobile microwave path 7, a microwave distribution unit 8, a control unit 9 and a processing unit 10 intermediate and low frequency. In the device, the signal of the reference channel is formed and the measurement signal is fed to the tested HEADLIGHT 3. To eliminate the amplitude instability of the coefficients. The transmission path 7, which plays a spurious role, uses an automatic gain control system (AGC) in the microwave unit 6. To do this, the mixture of the measuring signal and the AGC signal simultaneously passes the path of the adjustable amplifier of the RF microwave 6, and then the AGC signal is filtered out. After equalization coefficients. the transmission and phase shifts of the measuring channels in each of these channels are allocated levels proportional to the values of the quadrature components of the microwave field vectors in the openings PAR 3. 1 sludge.

Description

to

the first detector 57, the second detector 58, the first low pass filter 59 the second low pass filter 60, the first DC amplifier 61, the second UPT 62, the first analog to digital converter (ADC) the second ADC 64, the frequency divider 65 TO.

The device works the next time.

In the beginning we consider the formation of the signal of the reference channel. The signal from the microwave generator 1 passes through the power amplifier, the second directional 5 coupler 12, the third directional coupler 34t the second ferrite circulator 44, the first ferrite circulator 23, the second valve 19, each section 42, the third valve 29 at the output of which microwave -signal reference channel has the form

20

The invention relates to antenna measurements and can be used to measure PAR parameters in the near field on automated stands.

The purpose of the invention is to improve the measurement accuracy.

The drawing shows a structural electrical block diagram of a multi-channel device for measuring the amplitude-phase distribution, (AFR) field of a phased antenna array (PAR).

A multichannel device for measuring the amplitude-phase distribution of the field HEADLIGHTS includes a microwave generator 1, a power amplifier 2, the test phased array 3, a scanner carriage 4, a probe collimator 5, a microwave unit 6, a mobile microwave path 7, a microwave unit 8 distribution, control unit 9, intermediate and low frequency processing unit 10, first directional coupler 11, second directional coupler 12, first valve 13, first mixer 14, first IF amplifier 15, second mixer 16, first two-bit phase shifter 17, second IF amplifier 18, second valve

19, first adjustable IF amplifier

20, the first AGC detector 21, the first frequency divider 22 by 2, the first ferrite circulator 23e, the first microwave adder 24, the first quadratic detector 25, the one-bit phase shifter 26, the microwave first switch 27, the controlled phase shifter 28 by 90 °, the third valve 29, the second quadratic detector 30, the second microwave adder 31, the second adjustable IF amplifier 32, the IF accumulator 33, the third directional coupler 34, the first band-pass filter 35, the fourth valve 36, the second AGC detector 37, the second two-bit phase shifter 38, the second band-pass filter 39, fifth valve 40 am 41 litudny modulator section diode 42, the sixth valve 43, the second

ferrite circulator 44, submodule - 0 "basic manipulation when switching

) VTKB (t) cosCwet +) H

25 where V, is the amplitude of the signal o / 2 17 is the frequency of the microwave generator signal; K0 (t), -f0 (t) temporal amplitude and phase instabilities due to deformations of the rolling

30 microwave path 7 communication when moving the scanner carriage 4; t - time

Next, the signal (1) is subjected to double phase manipulation with the help of the first two-digit phase shifter 17 of switching the phase shifts of 0-180 °, 0-90 ° with signal frequencies

the catch coming from the divider on m and the second divider on 2:

46 hours - 47 hours

40

J4 (t) VlKc (t) cosCu) 0t + | +

ii 2 +

4 and

45

X

 ii s

- sin n I, t n

+ 04

n,

X M / n sinn- t + u (t),

P 1,3,5

where 92, b, / 4 - indexes fator 45, frequency divider 46 by t, second frequency divider 47 by 2, frequency divider 48 by p, logic switch 49, frequency divider 50 by q, third frequency divider 51 by 2, divider 52 frequencies on 1, IF-switch 53, n adjustable IF amplifiers 54, adjustable IF-phase rotator 55, phase shifter 56 by 90 °,

180 and 90 ° Јl, / 2ff ft, / switching frequency, respectively

Specifically, the switching frequency of the phase shifts at the frequency of the gg of the torus submodus, which is a 20 MHz crystal oscillator, and the division factor m 60, can be respectively 90 ° 333.33 kHz and 180 ° 166.66 kHz.

the first detector 57, the second detector 58, the first low-pass filter 59, the second low-pass filter 60, the first DC amplifier 61, the second UPT 62, the first analog-to-digital converter (ADC) 63, the second ADC 64, divider 65 frequencies on K.

The device works as follows.

In the beginning we consider the formation of the signal of the reference channel. The signal from the microwave generator 1 passes through the power amplifier, the second directional 5 coupler 12, the third directional coupler 34t, the second ferrite circulator 44, the first ferrite circulator 23, the second valve 19, the diode section 42, the third valve 29s at the output of which the microwave signal the reference channel has the form

0

) VTKB (t) cosCwet +) Hl)

where V, is the amplitude of the signal o / 2 17 is the frequency of the microwave generator signal; K0 (t), -f0 (t) temporal amplitude and phase instabilities due to deformations of the rolling

Microwave path 7 when moving the scanner carriage 4; t - time

Next, the signal (1) is subjected to double phase manipulation using the first two-bit phase shifter 17, which switches the phase shifts from 0-180 °, 0-90 ° with the signal-receiving frequency from the divider to m and the second divider by 2:

46 hours - 47 hours J4 (t) VlKc (t) cosCu) 0t + | +

ii 2 +

4 and

five

X

 ii s

- sin n I, t n

(2)

+ 04

n,

X M / n sinn- t + u (t),

P 1,3,5

where 92, b, / 4 - indices of phase manipulations when switching

The samples are 180 and 90 °, respectively, Јl, / 2ff ft, / switching frequency.

Specifically, the switching frequency of the phase shifts at the frequency of the submodulator, which is a 20 MHz crystal oscillator, and the division factor, m 60, can be, respectively, 90 ° 333.33 kHz and 180 ° 166.66 kHz.

A signal of the form (2), passing the fourth valve 36, the third directional tap 1-1, in the opposite direction arrives at the input of the ferrite circulator 23, passes the mobile microwave path 7 of the communication, the ferrite circulator 44, other output of which he takes on the form

U3 (t) V3K20 (t), 0t + | +

2f. (T) j.

The square of the amplitude instability and the double phase instability in the expression (3) correspond to the double passage of the signal through the mobile microwave communication path in the forward and reverse directions.

The other input of the microwave adder 31. Receives a signal from the directional branch 34, a passed valve 40, a two-bit controlled microwave phase-shifter 38, a valve 43 and also subjected to double phase manipulation with the same indices, but with different modulating frequencies coming from the output of the splitter 48 frequency at p and the output of the third divider 51 to 2:

U4 (t) V4cos Wot + y + - +

one

L 1,3,5 K

Ј sinKSl2t +

(four)

I

fcs, 3, s

 t

Ј sin K -2-tJ,

and at the output of the quadratic detector 30, the signal becomes proportional to U5 (t) | .

An adjustable IF amplifier 32 with its selective load allocates a signal at a frequency of

. 2 and

ten

15

s

20

25

thirty

35

40

45

The output signal of the adjustable inverter amplifier 32, configured to

I, -L, „- frequency takes the form:

Ufc (t) V6 K20 (t) cos2 and (t) cos (- ™ 3) t- - VeK | (t) (t) sin () t - (6) V (K (t) cos + 2C, (t).

From the output of the adjustable IF amplifier 32, the signal goes to the AGC detector, which produces a level proportional to 1 / K2o (t), thus causing the amplifier 32 to change its gain factor, maintaining a constant amplitude of the output signal

U7 (t) v7cos () t-H2i / 0 (t) (7)

In this case, the frequency of the signal (7) is 27.77 kHz. Next, signal (7) is transferred to a frequency equal to the total frequency from the interaction of signals with frequencies of 27.77 and 138.88 kHz, i.e. equal to 166.66 kHz. The second time using the mixers 16 and the IF amplifier 18, the signal is transferred to a frequency equal to the difference frequency from the interaction of the signals, 166.66 and 111.11 kHz, i.e. equal to 55.55 kHz. To the other input of the mixer, a signal is supplied from the divider 52 frequencies to 1 (1,180). Thus, at the output of the second control, the signal can be written in the form:

where Я4 / 2 is the frequency of the signal coming from the output of the frequency divider on p.

Specifically, the frequency of g - p

 72 b

may be 277.77 kHz, t is 138.88 kHz.

The output of the microwave adder 31 is allocated the sum of the signals

Us (t) UjCt) + U4 (t),

(five)

U. (t) Vecos

The signal at the output of the frequency divider 22 can be represented as follows:

9 (t) V9cos () t + (t) j. (eight)

The frequency of the signal (9) in this case is equal to 27.77 kHz, while it can be seen that only the phase is present in it

the instability of the mobile reference microwave path.

Consider the formation of a measuring signal coming from a directional coupler 12 to the studied PARAM 3, the receiving probe collimator 5, at the inputs of controlled discrete microwave phase shifters of which can be represented as:

U; o (t) V,

U c (t) V, 0K; K; cos u; ot4. (F; + i /; (9)

where K ..,; - initial attenuation constants of signals of measuring channels K x ... K - attenuation coefficients of signals of measuring channels j

(initial phase constants

U, (t)

I,

vXK; cos wet + 5 + 6a4 sinK-2-2t + v kVhKXcoe {4t + 4

and ;, (t.

vf1K; K; cos u 0t + | + v ,, K; Kjcoet4t + w

Sit

where 5 is the switching frequency of the sampling s coming from the output of the logic switch 49, -, F is the switching frequency of the outputs of the modulating signals from the logical switch 49.

Signals of the form (10) with the help of the microwave switch 27 alternately connecting the switching signals of the measuring channel to the phase shifts of the signals

catches determined by phase distribution; 1 - number measuring floor PAR; foot channel,

In controlled single-bit phase shifters 26, only one 180 ° th phase shift switch is used. The control signals to the phasers are supplied from the outputs of the logic switch, which alternately connects the signal from the frequency divider to 2 inputs

each controlled microwave phase shifter The control of the switching of the modulating signal is performed by a signal from frequency divider 50 per q (q 400). So on the outs

Controlled discrete microwave phase shifters signals can be written in the following form:

I,

4 sinK-2-2t + v 4

(ten)

h

3 S

| sinK-1 -n / i + t / ij

} -,

- T It I T

  Y t,

They are input to another controlled discrete microwave phase shifter, which also has one phase discrete (0-90 °). At the input of this controlled discrete microwave phase shifter, taking into account that the microwave switch operates in time with the supply of control (modulating) signals to single-digit phase shifters 26, the signal can be represented as:

At the output of the controlled phase shifter 28 by 90, the signal is described by the expression

u13 (tW

V13KXvcosOct + i.fl + flt | i ЈsinKatt + 02 | Ј IsinK-S + Mp

Ks -Sf 5K i i

(12)

V13KXc ° s 4t + 5 + Z + eit Z | sinKfl, t + e4 Ј insinK4W O chi k.f (S / j, e.5

T t

one

H

Thus, a signal of the form (12) appears to be subjected to virtually the same dual phase shift keying. The difference of the signal of the shape of (12) from a signal of the shape of (4) is actually that the signal (12) is subjected to additional amplitude and phase shift simultaneously with frequency ( low frequency) coming from the frequency divider by q and forming a multi-channel sequential structure of the measuring signal. The formula (12) also shows that the depth (or indices) of the amplitude-phase manipulation of the measuring signal is low modulating frequency depends on

V, 4 KXyCOs t +% (t), - i /; - JK (t);

uu (t) h

vnKiK s i ™ t +) -; - to, with

In order to get rid of the coefficient K0 (t) in expression (13), i.e. From the amplitude instability of the transmission coefficient of the moving microwave path 7 of the communication, which plays a parasitic role, an automatic gain control system (AGC) is intended, consisting of an amplitude modulator 41, a second band-pass filter 39, an IF adder 33, a first band-pass filter 35 and a detector 21 AGC. From the diode section 42, a level proportional to 1 / K0 (t) is allocated. This level using amplitude

K i i

T t

one

H

 T. i

attenuation coefficients and phase shifts determined by the AFR field of the HEADLIGHTS, as well as from the attenuation constants and initial phase shifts of the microwave paths of the measuring channels. The latest sources of modulation of the measuring signal must be eliminated, which will be further produced by the IF measuring signals.

Taking into account only the frequency component, nentu containing II, which

then it will be allocated by an adjustable IF amplifier 20, the signal at the output of the quadratic detector 25 will be described by the expression

T21

t. t «-г

1G

(13)

-T t 4 T.

modulator 41 and bandpass filter is converted into a 100 kHz sinusoidal signal and added to the measuring signal 04) in the Q ГГЧ-adder 33. Moreover, the control input of the amplitude modulator receives a signal from the output of the frequency divider by K (K 200). The mixture of the measuring signal and the AGC signal simultaneously passes the path of the adjustable IF amplifier 20, then the AGC signal (100 kHz) is filtered out by the first bandpass filter 35, turned back into a level proportional to 1 / Ka (t) using the AGC detector 21 and causes the adjustable IF -amplifier 20 to change its transmission coefficient, maintaining the amplitude of the output signal, which does not depend on the value of K0 (t).

uf (t)

Thus, the signal type

Vf5KXcos - - + (t)

one

(14)

T

 t 1

g g

vfJKXcoe | --Ј t + u. (t) -;

T - 1

 t 4Т

arrives at the input of the IF switch 53, there is a temporary separation of the block of the 10 IF and LF processing of the helix channels through the intermediate

frequency and is controlled by the same frequency IF switch 53 performs the same as the microwave switch 27. Real-time conversion with respect to the signals at the outputs of the IF switch to the microwave switch 27, i.e. it is written as follows:

 (t

 | vKK; K; cos - t + (,. t -i /; - 4 o t "l

U, 26 (t

and;

vtt K; K; COS + v. (t) - v; - t t

 i ir-T

0

The bandwidth of the tunable n t-amps 54 is designed only for a possible change (change rate) of the measured parameters 1p and does not capture the spectral components of frequency F. Therefore, at the outputs of the tunable amplifiers, the IF signals will have a continuous appearance

U | 7 (t) Vn kHsoD- ™ H + / l, (t) -i / x-X

2p t) (16)

u; 7 (t) Vn K K; cos - r-V (t) -u x-cfj55

Moving the scanner carriage 4, each measuring probe to the collimatics of the output signal, does not depend on the value of K0 (t).

one

T

 t 1

g g

(15)

five

0

five

 i ir-T

torus 5 is shown in one point of the aperture of the HEADLAMP, where it is possible to assume that K x and measuring channels are the same. By adjusting the gain of the amplifiers 54 and adjusting the IF phase shifters 55, the phasing amplitudes of the measuring channel signals are equal. To achieve high calibration accuracy, several iterations can be performed at various points in the aperture of the HEADLIGHTS. An oscilloscope and a voltmeter can be used as an indicator device for calibration.

Thus, after equalizing the gains and phase shifts of the measuring channels, the signals at the outputs of the tunable IF-phase shifters 55 are written as follows:

and ;, (t) -v ,, K; cos - t + (/ e (t) - (I

L

Next, the signals (18) are subjected to phase detection using phase detectors 57 and 58, the output outputs of which receive signals of the form (9) 5 rotated relative to each other by 90 ° using phase shifter 56. After the low-pass filter 59 and 60, UPT 61 and 62 V for each measuring channel, it is possible to distinguish levels proportional to the values of the quadrature components of the vectors of the microwave field in the aperture of the PAR

A ×) B; Kjsin ifj (18)

These levels are converted to digital form using A / D converters 63 and 64 and are fed to a computer for further processing.

Claims (1)

Invention Formula A multichannel device for measuring the amplitude-phase distribution of a phased-array antenna field, containing a phased antenna array under test (PAR), a mobile microwave communication path, a series-connected microwave generator and a power amplifier, a scanner on which the probe collimator consisting of measuring probes and microwave switches, characterized in that, in order to improve the accuracy of measuring the amplitude-phase distribution of the field of the PAR, in it are connected to the output of each of the measuring x probes single-bit phase shifters, the outputs of which are connected to the corresponding inputs of a microwave switch, a controlled phase shifter at 90 °, connected to the output of a microwave switch, a microwave unit containing a series-connected first valve, first microwave adder, first quadratic detector, intermediate adder frequencies, the first adjustable IF amplifier, the first band-pass filter and the first ) ten 20 25 thirty 35 40 45 50 55 an AGC detector, the output of which is connected to the control input of the first adjustable IF amplifier, are connected in series the first ferrite circulator, the second valve, the diode section, the third valve, the first two-digit phase shifter, the fourth valve and the first directional coupler, the first output of which is connected to the second input of the first microwave adder, the second output with the second input of the first ferrite circulator, serially connected amplitude modulator and the second band-pass filter, the output of which is connected to the second The first input of the intermediate frequency adder, the first input of the amplitude modulator is connected to the IF and the input of the diode section, the microwave distribution unit containing the second directional coupler connected in series, the third directional coupler, the second ferrite circulator, the second microwave adder, the second quadratic detector, the second adjustable IF amplifier, the first mixer, the first IF amplifier, the second mixer, the second IF amplifier, and the first frequency divider by two, in series connected the fifth valve, whose input is It is connected to the second output of the third directional response of the ITEL, the second two-bit phase shifter and the sixth valve, the output of which is connected to the second input of the second microwave adder, as well as the second detector of the ARUP connected between the output of the second adjustable IF amplifier and its control input, the control unit containing a series-connected submodulator, a frequency divider by m and a second frequency divider by two, a serially connected frequency divider by p, a third frequency divider by two, and a logic switch, as well as cases the frequencies are on k, q and 1, the inputs of the frequency dividers on p, k and 1 are connected to the output of the submodule, and the frequency divider on 2 is connected between the output of the frequency divider on p and the control input of the logic switch, the IF and LF processing unit, containing an inverter switch, n series-connected adjustable amplifier IF, IF phase shifters, the output of each of which is connected to the inputs of the corresponding 1- and 2nd p detectors, the outputs of which are connected to series-connected respective first and second low-frequency filters (LPF) p to the first and second DC amplifiers and the first and second analog-digital converters, respectively, as well as the phase shifter 90 °, heterodyne the input of the second detector is connected to the output of the phase shifter by 90 °, the heterodyne input of the first detector is connected to the output of the first frequency divider by 2 e inputs of the tunable IF amplifiers are connected to the outputs of the IF commutator Topas; The power switch is connected to the input of the second directional coupler, the heterodyne inputs of the first and second mixers are connected respectively to the outputs of the third frequency divider by two and the frequency divider by 1, 180 and 90-degree inputs of the second two-bit phase shifter are connected respectively to the outputs of the frequency dividers p and the third frequency divider by 2, the output of the first divider two frequencies are connected to the input of the phase shifter by 90 °, the second output of the second directional coupler is connected to the input of the test phased array, the second output of the first ferrite circulator and the second output of the second ferrite circulator are connected via a mobile microwave path, signal and control The inputs of the switch IF are connected respectively to the output of the first adjustable IF amplifier and the output of the frequency divider to q, the output of the frequency divider by k is connected to the second input of the amplitude modulator, 180- and 90-degree inputs of the first two-channel The phase shifter is connected to the outputs of the frequency divider by m and the second frequency splitter by 2, respectively; the control inputs of the one-digit probe-collimator phase shifters are connected to the outputs of the logic switch, the control inputs of the microwave switch and the controlled phase shifter by 90 are connected respectively to the outputs of the logic switch frequencies on q and frequency divider on p.