DE1541469B2 - Radar arrangement with alternating antenna connection to the transmitter and receiver - Google Patents

Description

PA ₁₆ ) is provided, which is between The invention relates to a radar transmitter-receiver arrangement with an antenna with at least one pair of antenna connections that are alternately connected to a transmitter and a receiver, with a four-armed balanced hybrid junction in the connection is inserted whose decoupled arms with the transmitter and

PA ₂ , PA ₄ .

the transmission phase and the reception phase of each radar period a phase change of π in the

antenna feed circuit connected to one (2; 12, 22, 32, 42) of the two other 25 the receiver and its two other arms with arms of the hybrid branch (T; T ₁ , T ₂ , T ₃ , T ₄ ) the two connections of the antenna connection pair generated.
2. Radar transceiver arrangement according to An

Claim 1 for an antenna with electrical beam are connected.

In radar transceiver arrangements in which in each radar period during a short

Pivoting, which contains several radiators, from 3 ° transmission phase of the transmitter to the transmission of the strong which each in the feed circuit a controllable phase transmission pulse and then during a reception

containing a phase control arrangement is provided which phase control signals to the control inputs of the controllable phase shifter the receiver for receiving the echo signals are connected to the same antenna, if there is a problem, the

lays through which the high power transmitted pulse from the phase shifter 35 from the input of the Empergenerated To keep phase shifts away accordingly and during the reception of the radiation direction to be set in the corresponding radar period,

characterized in that the phase switching phase completely absorbs the weak echo signals to be transmitted to the recipient's entrance. For this purpose are generally special broadcasts

arrangement (I; V) in the connections between 4 ° receive switches or send / receive switchover

ter provided that either on the basis of external control signals or automatically by taking advantage of different Make the necessary separations for the properties of the transmitted and received signals. For this purpose, arrangements with gas discharge tubes, ferrites or semiconductors are generally used used.

One from the book "Introduction to Monopulse" by D. R. Rhodes, McGraw-Hill Verlag, 1959,

the control inputs of the phase shifter (PA ₉ ... PA ₁₆ ; PA ₂ , PA ₄ ... PA ₁₆ ), which are in the feed circuits of the one (2; 12, 22, 32, 42) of the other two arms of the hybrid branch (T; T ₁ , T ₃ , T ₄ ) connected radiators (S ₉ ... S ₁₆ ;

S ₂ , S ₄ "... S ₁₆ ) and the corresponding
Outputs of the phase control arrangement (C) inserted and designed so that they are from the
Phase control arrangement (C) output control signals in the sense of a phase change by π ver 50 p. 59, known arrangement of the initially indicated. nen type is intended for a monopulse radar system,

3. Radar transceiver arrangement according to An, in which the receiver has two inputs, namely claim 2, characterized in that in the case of a sum input and a differential input, quantized phase shifters are reversed, the sum input being the sum and the difference (PA ₁ ... PA ₁₆ ) the phase switching arrangement (/; / ') 55 remote input contains the difference between the signals received from two separate signals for each phase shifter, one non-equivalence switching antenna halves, from which an input is used, while when transmitting, the transmitting power of the speaking output of the phase control arrangement is fed to the whole antenna. The balanced voltage (C) is connected, the other input of which, the hybrid branch, is used for the sum and the phase ^switching effecting control difference formation: the sum input of the receive signal from the transmitter synchronization (SE) receiver is with one of the two decoupled arms

■ - - ■ the hybrid junction and its differential input

connected to the other of these two arms; and the output of the transmitter is on the "buzz" arm connected to the hybrid junction. The problem of separating the sender and receiver remains in

and the output of which is connected to the excitation input of the element of the quantized phase shifter which causes a phase change of π.

4. Radar transceiver arrangement according to one of claims 1 to 3 for a radar system, whose receiver has several inputs on this case in full, since without special Precautions to use the full transmitter power

The sum input of the receiver would arrive and when receiving the transmitter output would be connected in parallel to the sum input of the receiver. Therefore, in the known arrangement, there is a “/ ITÄe” switch in the connection between the transmitter output and the “buzz” arm, and a “TR ” switch is connected upstream of each of the two receiver inputs.

In all of these known arrangements, the transmit-receive switch or the transmit-receive switch be designed for the entire transmission power, which is the case with radar transmitters with high pulse power is technically difficult to implement and requires considerable effort.

The object of the invention is to create a radar transceiver arrangement which the Transmit / receive switchover made possible without a transmit / receive switch.

In an arrangement of the type specified at the beginning, this is achieved according to the invention in that one decoupled arm of the hybrid junction is permanently connected to the output of the transmitter and the other decoupled arm is permanently connected to an input of the receiver and that a phase switching arrangement controlled by the transmitter synchronization arrangement is provided which generates a phase change by π in the antenna feed circuit connected to one of the other two arms of the hybrid junction between the transmission phase and the reception phase of each radar period.

In the arrangement according to the invention, the property of the balanced hybrid branches is used that the power supplied to one of the two decoupled arms is divided between the two other arms without anything reaching the other decoupled arm, while the signals supplied to these two other arms, depending on whether they are in phase or out of phase, are transmitted completely and exclusively to one or the other of the two decoupled arms. The phase switching by π between the transmission phase and the reception phase in the arrangement according to the invention ensures that the signals fed to the two other arms of the hybrid branch during reception are in phase opposition and thus reach the receiver, while the transmission pulse is completely kept away from the receiver. The phase switching can be done with relatively simple arrangements.

The invention can be used with particular advantage in radar systems whose antennas already contain controllable phase shifters for changing the phase position of the signals transmitted via the antenna feed circuits, because the existing phase shifters can then be used for phase switching. This applies in particular to an antenna with electronic beam swiveling which contains several beams, each of which contains a controllable phase shifter in the feed circuit, a phase control arrangement being provided which applies control signals to the control inputs of the controllable phase shifter, through which the phase shifts generated by the phase shifters accordingly the radiation direction to be set in the corresponding radar period. In this case, the arrangement according to the invention is preferably designed so that the phase switching arrangement is inserted into the connections between the control inputs of the phase shifters, which are in the feed circuits of the beams connected to one of the other two arms of the hybrid branch, and the corresponding outputs of the phase control arrangement and is designed so that it changes the control signals emitted by the phase control arrangement in the sense of a phase change by π .

The invention is suitable for radar systems in which the sum of all received signals is fed to a single receiver input, as well as for radar systems, such as the monopulse radar systems, where the receiver has multiple inputs, each one from a part of the antenna intercepted signals are fed, while the transmission pulse is applied to the whole antenna. In this case, the arrangement according to the invention is preferably designed so that for each receiver input a pair of antenna connections and an associated balanced hybrid junction are provided and that a decoupled arm of each hybrid branch is continuously connected to an input of the Receiver and the other decoupling arms of all hybrid branches via a power splitter arrangement are permanently connected to the output of the transmitter.

The invention is described below by way of example with reference to the drawing. In it shows

F i g. 1 shows the basic diagram of a radar transceiver arrangement designed according to the invention with an antenna with electronic beam steering and

F i g. 2 shows the basic diagram of a radar transceiver arrangement according to the invention for a Monopulse radar system.

1 shows the structure of a radar antenna with electronic beam swiveling, which contains 16 radiators S ₁ to S ₁₆ , which are formed, for example, by dipoles of length λ / 2 when λ is the operating wavelength. Only some of these emitters are shown.

These radiators are arranged in front of a reflector P.

A controllable phase shifter Ph ₁ (i = 1, 2 ... 16) is arranged in the feed branch of each radiator.

The expression “controllable phase shifter” is to be understood as any arrangement which gives a signal passing through a phase change which depends on a control signal fed to a control input of the phase shifter. The signal terminals of the phase shifter that are not connected to the radiators are connected to a power distribution arrangement made up of power dividers d ₂ to d _is , which are shown here in the form of T-members, each of which distributes the power supplied to its input branch evenly to its output branches . The phase shifters Ph ₁ and PA _{3 are connected} to the outputs of the power divider d ₈ , the phase shifters PA ₂ and PA ₄ to the outputs of the power divider d ₉ , etc., until finally the phase shifters PA ₁₄ and PA ₁₆ to the outputs of the eight power dividers d _s to d ₁₅ are in turn connected in pairs to the outputs of four power dividers d _v d _s , d _e , d ₇ , and their inputs are connected in pairs to the outputs of two power dividers d ₂ and d ₃ . Consequently

the power supplied to the inputs of the power splitter d ₂ and d ₃ during transmission is evenly distributed to the associated radiators, but with a different phase position due to the setting of the various phase shifters PZz ₁ to PZz ₁₆ . When receiving, the vector sum of the signals picked up by the various radiators appears at the "input branches" of the two power splitters d ₂ and d ₃ with the phase position determined by the setting of the phase shifters.

The input branches of the two power splitters d ₂ and d _s , which to a certain extent form two antenna connections, are connected to arms 2 and 3 of a balanced hybrid branch T , which is shown here as a four-armed "magic T" link. The transmitter E and the receiver R are connected to the decoupled sleeves and 4 of this hybrid branch T. As is well known, such a hybrid branching works in such a way that the signals fed to arm 1 are evenly divided between arms 2 and 3, while signals fed to arms 2 and 3 are completely on arm if they are in phase and completely on arm 4 if they are in phase opposition appear while the other arm receives nothing.

A phase control arrangement C, which is synchronized by a synchronization output SP of the transmitter E , applies control signals to the control inputs of the phase shifters Ph ₁ to PZz ₁₆ , by means of which the phase shifters are set so that the desired radiation direction of the radiation diagram results in each radar period. However, the outputs of the phase control arrangement C are only directly connected to the control inputs of those phase shifters PZz ₁ to Ph ₈ which are assigned to the power divider d _3. A phase switching arrangement / with eight inputs and eight outputs is inserted into the connections to the control inputs of the remaining phase shifters PZz ₉ to Ph ₁₆ , which are assigned to the power divider d _2. The phase switching order / is designed so that in the idle state it transmits the control signals coming from the phase control arrangement C unchanged, while in the working state it changes these control signals so that they change the phase shift by η in the phase shifters Ph _a to Ph ₁₆ with respect to the phase shift caused by the unchanged control signals. The phase switching arrangement / thus has the same effect as a corresponding number of additional phase shifters with the phase shift ± π, which are each connected in cascade with one of the phase shifters PZz ₉ to Ph ₁₆ and are switched on and off as required.

The phase switching arrangement / is controlled by a further synchronization output SE of the transmitter E so that it is in the idle state in the transmission phase of each radar period and in the working state in the reception phase. In the transmission phase, thus the emission of the transmit pulse _ι (i = 1, 2 ... 16) in each of the phase shifters is carried out with the order determined by the phase control arrangement C phase shift φ pzz _1; when receiving, the phase shifters PZz ₁ to Ph _{8 have} the same phase shift φι '= <pi, while the' phase shifters PZz ₉ to PZz _{18 have} the phase shift φ {= φ _ι ± π .

The signals in arms 2 and 3 of the hybrid branch, which are in phase when transmitting, when arm 1 is fed by transmitter E , are therefore in opposite phase when receiving. Therefore, all the energy received goes into arm 4, which is connected to the recipient /? connected is. This follows naturally from the working principle of the balanced hybrid branches.

Of course, an absolutely similar result would be obtained if the phase shift in the reception in the feed branches of the radiators S ₁ to S _{5 were changed} by π , while the phase shift in the feed branches of the radiators S ₉ to S ₁₆ remained unchanged.

This eliminates the need for the transmit / receive switch that is usually required is required to feed the entire output power of the transmitter to the antenna during transmission and to keep them away from the receiver while they receive the entire reception power Recipient.

Ei the embodiment of FIG. 1 it is assumed that the sum of all signals received by the radiators is formed during reception and fed to a single input of the receiver R. In this case, a single hybrid branch T is required.

In certain cases, however, the sub-sums of the received from different radiator groups Signals are generated and fed to various receiver inputs. This is especially true in the case of the so-called monopulse radar systems.

As an example in FIG. 2 shows a monopulse radar antenna with electronic beam swiveling according to the elevation angle and the lateral angle. In this case nothing is changed during transmission, but during reception it is necessary to form the partial sums of the signals received by each quarter of the radiator field, i.e. the sums of the signals from radiators S ₁ to S ₄ from the radiators S ₅ to S ₈ , by the radiators S ₉ to S ₁₂ and by the radiators S ₁₃ to S _{16 are} received. These partial sums must be fed separately to four inputs of the receiver RM.

The power dividers d _i to d _{7 are} therefore replaced by four-armed magic T-links (or other hybrid branches with four balanced arms) T ₁ to T ₄ . Each arm in one of these hybrid branches then has the same function as the relevant arm of the hybrid branch T from FIG. 1.

The hybrid branch T of FIG. 1 is then superfluous and can be replaced by a simple power splitter d _x , to whose input the output of the transmitter E is connected directly. The arms 11 and 21 of the hybrid branches T ₁ and T ₂ are connected to the power splitter d _a and the arms 31 and 41 of the hybrid branches T ₃ and T _{4 are} connected to the power splitter d ₂ , and the branches 13, 12, 23, 22, 33 , 32, 43, 42 are connected to the power dividers d ₈ , d ₁₀ , d _s , d _lv, d ₁₂ , d _u , d ₁₃ and d _ls , respectively. The arms 14, 24, 34 and 44 are each connected to one of the inputs of the receiver RM .

A phase switching arrangement / ', which is the same as the phase switching arrangement / of FIG. 1, is now inserted in front of the control inputs of the phase shifters PZz ₂ , PZz ₄ , PZz ₆ ..., ie the phase shifters with an even index. In this way, when receiving, the signals coming from the radiators are no longer added up in the one connected to the transmitter.

that arm of the relevant T-link but in the fourth arm, i.e. in the arm 14, 24, 34 or 44 connected to the receiver RM.

If one then denotes the signal received by the radiator S ₁ - (i = 1 to 16) with b _{i, one obtains}

IO

at 14 a signal B ₁ = b ₁ + b ₂ + b ₃ + b _i
at 24 a signal B ₂ = b ₅ + b ₆ + b ₁ + b ₈
at 34 a signal B ₃ = b _g + b _1Q + b _n + O
at 44 a signal B ₄ = O ₁₃ + O ₁₄ + O ₁₅ +

The signals B ₁ to B ₄ can be processed as sum and difference signals, as is known from monopulse radar systems.

The additional phase shift by + π upon reception in the phase shifters PA ₉ to PZz ₁₆ (FIG. 1) or in the phase shifters PA ₂ , PZi ₄ ... PZi ₁₆ (FIG. 2) can be obtained in various ways which are familiar to the person skilled in the art and the choice of which obviously depends on the type of phase shifter PZij used.

If, for example, it is a pulse-controlled quantized ferrite phase shifter ("latching" phase shifter), the phase control element of the phase shifter, which generates a phase shift of 180 °, is no longer controlled directly by the phase control arrangement C , but via a digital non-equivalence circuit, its other Input receives the control signal coming from output SE for switching the phase by π. If the phase shift φ _{ during transmission is less than 180 °, the non-equivalence circuit, which receives two identical signals (two "0"), does not excite the relevant phase control element. On the other hand, the control signal coming from output SE causes this excitation during reception. The reverse takes place when φ, is greater than 180 °. In all cases there is a change in the phase shift of 180 ° between transmission and reception.

In the above description, the simplest case has been assumed that the used balanced hybrid branches are designed so that a signal in the arm 1 two causes in-phase signals in arms 2 and 3.

However, other hybrid branches can also be used in which a signal in arm 1 is divided into two signals in branches 2 and 3, which have a certain mutual phase shift φ ₀ .

In this case it is of course necessary to compensate for this phase shift by acting on the corresponding phase shifters PZi _{1 -.}

The measures described above are always applicable when you have an antenna system with at least two connections, regardless of whether it is an antenna with or acts without beam swiveling. In the latter case, when the antenna circuit does not have a phase shifter contains, you can see a 180 ° phase shifter in the connection between one of the Connections and the connected radiators before, and this phase shifter is described in the above Way turned on when receiving.

For this purpose 2 sheets of drawings 509 521/150

Claims (1)

Patent claims: 1. Radar transceiver arrangement with an antenna with at least one pair of antenna connections that are alternately connected to a transmitter and a receiver, with a four-armed balanced hybrid junction being inserted into the connection, the decoupled arms of which with the transmitter and the Receiver and its two other arms are connected to the two connections of the antenna connection pair, characterized in that the one decoupled arm (1; 11, 21, 31, 41) of the hybrid branch (T; T ₁ , T ₂ , T ₃ , T ₄ ) is permanently connected to the output of the transmitter (E) and the other decoupled arm (4; 14, 24, 34, 44) is permanently connected to an input of the receiver (R; RM) and that a phase switching arrangement controlled by the transmitter synchronization arrangement (SE) (/, PA ₉ ... PA ₁₆ ; / ', has, characterized in that a pair of antenna connections for each receiver input ( ^rf 8> ^ i <>; ^d 9> ^d u> ^d i? ^d u> ^rf i3> ^ 15) ^{and an} associated balanced hybrid branch (T ₁ , 5 T ₂ , T ₃ , T ₄ ) are provided and that a decoupled arm (14, 24, 34, 44) of each hybrid branch is permanently connected to an input of the receiver (RM) and the other decoupled arms (11, 21, 31, 41 ) of all hybrid branches are permanently connected to the output of the transmitter (E) via a power splitter arrangement (^ ₁ , d ₂ , d ₃ ) .