CN106199188A - A kind of device and method utilizing the change of removal cable phase place in circulator calibration vector field measurement - Google Patents

Abstract

A kind of device utilizing the change of removal cable phase place in circulator calibration vector field measurement, combines including radio frequency frequency and local oscillator frequency is combined；Radio frequency frequency is combined and is connected with the first directional coupler, and the straight-through end of the first directional coupler is connected with removal cable, and coupled end is connected with parametric mixer；Removal cable is connected to the port one of circulator, the port two of circulator is connected to the second directional coupler by amplifier, the straight-through end of the second directional coupler is connected with radio frequency doubler, and coupled end is connected with the port three of circulator, and radio frequency doubler is connected to receiver；The medium frequency output end of parametric mixer is connected to capture card；Local oscillator frequency is combined and is respectively connecting to local oscillator doubler and parametric mixer by power splitter, and local oscillator doubler is connected to receiver；Receiver is connected to capture card by IF process module.The present invention improves the signal to noise ratio of reflected signal, solves that the reflected signal when removal cable is long is too small and the problem that cannot detect.

Description

A kind of device utilizing the change of removal cable phase place in circulator calibration vector field measurement And method

Technical field

The invention belongs to Terahertz field of measuring technique, be specifically related to one for Terahertz frequency range (containing millimeter wave, sub-milli Meter wave band) the device and method utilizing the change of removal cable phase place in circulator calibration vector field measurement.

Background technology

Vector field measurement refers to measure amplitude and the PHASE DISTRIBUTION of electromagnetic field simultaneously.This measurement technology is put down by scanning one The two-dimensional vector field shape of face, cylinder or sphere is measured, the radiation source to be measured 3 D electromagnetic field in full extent of space of can deriving Distribution and propagation characteristic thereof, be therefore widely used in large-scale reflector antenna, Feed Horn, millimeter wave imaging system and standard The measurement of the performances such as optical system.

Typical Terahertz plane vector field measurement system as it is shown in figure 1, wherein terahertz sources source be arranged on high accuracy On XY motorized precision translation stage, terahertz signal is produced by microwave signal frequency multiplication.During measuring, motorized precision translation stage is put down at selected Scan on face, and then obtain vector field information to be measured.The removal cable being connected to terahertz signal source can be along with translation stage one Rising mobile, owing to the phase place of removal cable can change with the change of the shape of cable, therefore the mobile meeting of cable is at Microwave Frequency Section introduces certain phase error.At microwave frequency band, this error is negligible, but at terahertz wave band, this phase Position error is amplified along with the frequency multiplication of signal.A small shake on the signal phase of 10GHz, will amplify on 1THz 100 times.The phase error that removal cable introduces can be varied from along with the difference of signal frequency multiplication number of times.Additionally, this phase place becomes Change also with scanning area about: the area of scanning is the biggest, and the phase error of introducing is the biggest.Therefore, the movement of removal cable The phase error introduced will the phase accuracy of serious vector field.

In order to effectively reduce the impact that the problems referred to above cause, it is necessary to removal cable is moved the phase error caused and carries out school Accurate.The way of a kind of simplicity is to increase an artificial impedance mismatching in terahertz sources source, makes the microwave signal of incidence have one Fixed reflection, is made this reflected signal return along same cable reflection, is surveyed by the phase place detecting this reflected signal Measure the phase error of the mobile introducing of this removal cable.But when the length of cable is long, due to the loss of cable itself, The intensity of reflected signal is the least and cannot accurately obtain its phase place, introduces bigger phase error on the contrary.If can be by this signal Amplified before being reflected back removal cable, then signal is injected removal cable, so can be effectively improved the letter of reflected signal Make an uproar ratio, and then calibration removal cable introduces phase error.

Summary of the invention

The present invention for deficiency of the prior art, it is provided that one utilizes in circulator calibration vector field measurement mobile electricity The device and method of cable phase place change.

For achieving the above object, the present invention is by the following technical solutions:

A kind of device utilizing the change of removal cable phase place in circulator calibration vector field measurement, it is characterised in that: include Radio frequency frequency is combined and local oscillator frequency is combined；Radio frequency frequency is combined and is connected with the first directional coupler, the straight-through end of the first directional coupler and mobile electricity Cable is connected, and coupled end is connected with parametric mixer；Removal cable is connected to the port one of circulator, and the port two of circulator passes through Amplifier is connected to the second directional coupler, and the straight-through end of the second directional coupler is connected with radio frequency doubler, coupled end and ring The port three of shape device is connected, and radio frequency doubler is connected to receiver；The medium frequency output end of parametric mixer is connected to capture card；This The frequency that shakes is combined and is respectively connecting to local oscillator doubler and parametric mixer by power splitter, and local oscillator doubler is connected to receiver；Receive Machine is connected to capture card by IF process module.

For optimizing technique scheme, the concrete measure taked also includes:

Described first directional coupler is dual directional coupler, and described parametric mixer includes parametric mixer one and reference Frequency mixer two, two coupled end of the first directional coupler are connected with parametric mixer one and parametric mixer two respectively.

The medium frequency output end of described parametric mixer one is connected to capture card, the medium frequency output end of described parametric mixer two It is connected with capture card by duplexer.

Described power splitter includes that the first power splitter and the second power splitter, local oscillator frequency are combined and be divided into two-way by the first power splitter, One tunnel is connected to local oscillator doubler, and the second power splitter of separately leading up to is divided into again two-way, respectively with parametric mixer one and reference Frequency mixer two is connected.

Described capture card is high-speed a/d capture card.

Described receiver includes HEB frequency mixer.

The coefficient of coup of described second directional coupler is suitable with the amplification of amplifier.

Additionally, also proposed a kind of employing above-mentioned to utilize removal cable phase place in circulator calibration vector field measurement change The calibration steps of device:

Radio frequency frequency is combined and is produced frequency microwave signal, and local oscillator frequency is combined and produced local oscillator microwave signal, frequency microwave signal and local oscillator After microwave signal is respectively through M frequency multiplication, the machine that is received produces intermediate-freuqncy signal, and wherein M is the frequency multiplication number of times of terahertz signal；

Frequency microwave signal flows into from the port one of circulator through removal cable, through amplifier and the second directional couple Device, is flowed through the port three of circulator, is re-introduced into removal cable, by parametric mixer two by the coupled end of the second directional coupler Receive；

Parametric mixer one exports system reference signal, parametric mixer two output mobile reflected signal；

Utilizing duplexer intermediate-freuqncy signal to be gathered by capture card together with mobile reflected signal, capture card also acquisition system is joined Examine signal；

Obtain phase information according to the signal that capture card collects, calculate and calibrate the introduced phase place of removal cable by mistake Difference.

Further, further:

Radio frequency frequency is combined and the initial phase of the comprehensive signal of local oscillator frequency is respectivelyAndThe phase place of system reference signal is:

$f_{ref}^0=f_{RF}^0-f_{LO}^0$

The electrical length of removal cable isThe radiofrequency signal phase place entering parametric mixer two is:

$f_{RF}^1=f_{RF}^0+2f_{RF}^l$

The phase place of parametric mixer two intermediate frequency output is:

$f_{ref}^1=f_{RF}^0-f_{LO}^0+2f_{RF}^l$

The phase place of the change through removal cable therefore detected is:

$f_{RF}^l=(f_{ref}^1-f_{ref}^0)/2$

The intermediate frequency phase place detected is f_IF, then the intermediate frequency phase place after calibration is:

$f_{IF}^{cal}=f_{IF}-{\mathrm{Mf}}_{RF}^l.$

The invention has the beneficial effects as follows: connect a circulator at removal cable end, utilize three port identities of circulator, Achieve and first reflected signal is amplified, then by signaling reflex.This device and method realizes simple, can be effectively improved reflected signal Signal to noise ratio, solves the long problem causing reflected signal too small of cable, can apply in large-scale vector field measurement system.

Accompanying drawing explanation

Fig. 1 is the system block diagram of general vector fields.

Fig. 2 is that vector field of the present invention measures system and removal cable phase alignment block diagram.

Fig. 3 is the block diagram of the specific embodiment of the invention.

Reference is as follows: radio frequency frequency combine 1, local oscillator frequency combine the 2, first directional coupler 3, removal cable 4, parametric mixer One 5, parametric mixer 26, circulator 7, amplifier the 8, second directional coupler 9, radio frequency doubler 10, receiver 11, collection Card 12, local oscillator doubler 13, IF process module 14, duplexer the 15, first power splitter the 16, second power splitter 17, reference mixing Device 18.

Detailed description of the invention

In conjunction with the accompanying drawings, the present invention is further detailed explanation.

As in figure 2 it is shown, utilize the device of removal cable phase place change in circulator calibration vector field measurement to include radio frequency frequency Combine 1 and local oscillator frequency combine 2, radio frequency frequency is combined and 1 is connected with the first directional coupler 3, and the first directional coupler 3 is dual directional coupler, Straight-through end is connected with removal cable 4, and two coupled end are connected with parametric mixer 1 and parametric mixer 26 respectively.

Removal cable 4 is connected to the port one of circulator 7, and the port two of circulator 7 is connected to amplifier 8, amplifier 8 Outfan and the second directional coupler 9 are connected, and its coefficient of coup is suitable with the amplification of amplifier 8.Second directional coupler 9 Straight-through end be connected with radio frequency doubler 10, coupled end is connected with the port three of circulator 7.Radio frequency doubler 10 is sequentially connected to Radiation source to be measured and can receive radiofrequency signal the receiver 11 being mixed, receiver 11 passes sequentially through IF process module 14 He Duplexer 15 is connected to capture card 12, and capture card 12 can use high-speed a/d capture card.

The medium frequency output end of parametric mixer 1 is connected to capture card 12, and the medium frequency output end of parametric mixer 26 passes through Duplexer 15 is connected with capture card 12.Local oscillator frequency is combined 2 and is divided into two-way by the first power splitter 16, and a road is connected to local oscillator doubler 13, the second power splitter 17 of separately leading up to is divided into again two-way, is connected with parametric mixer 1 and parametric mixer 26 respectively.

When using apparatus above to measure, radio frequency frequency combines 1 generation frequency microwave signal, and local oscillator frequency combines 2 generation local oscillators After microwave signal, frequency microwave signal and local oscillator microwave signal are respectively through M frequency multiplication, it are received machine 11 and produce intermediate-freuqncy signal, Wherein M is the frequency multiplication number of times of terahertz signal.

Frequency microwave signal flows into from the port one of circulator 7 through removal cable 4, through amplifier 8 and the second orientation Bonder 9, is flowed through the port three of circulator 7, is re-introduced into removal cable 4, by reference by the coupled end of the second directional coupler 9 Frequency mixer 26 receives.Parametric mixer 1 exports system reference signal, parametric mixer 26 output mobile reflected signal；Profit Intermediate-freuqncy signal being gathered by capture card 12 together with mobile reflected signal with duplexer 15, capture card 12 also acquisition system is with reference to letter Number.

The signal that capture card 12 collects is time-domain signal, after FFT, obtains the phase information of each signal.System System phase analysis is as follows: the devices such as circulator, directional coupler and power splitter maintain static, when radiofrequency signal is through these devices Time, only can increase a fixing phase place, the phase place finally detected system does not affect, and does not considers.

Assume that radio frequency frequency is combined and the initial phase of the comprehensive signal of local oscillator frequency isAndThe phase place of system reference signal is:

$f_{ref}^0=f_{RF}^0-f_{LO}^0$

The electrical length (can be equal to the phase place of removal cable 4 at this) assuming removal cable 4 isEnter with reference to mixing The radiofrequency signal phase place of device 26 is:

$f_{RF}^1=f_{RF}^0+2f_{RF}^l$

Wherein coefficient 2 is because signal through removal cable 4 twice, the phase place of parametric mixer 26 intermediate frequency output be:

$f_{ref}^1=f_{RF}^0-f_{LO}^0+2f_{RF}^l$

The phase place of the change through removal cable 4 therefore detected is:

$f_{RF}^l=(f_{ref}^1-f_{ref}^0)/2$

Assume that the intermediate frequency phase place detected is f_IF, then the intermediate frequency phase place after calibration is:

$f_{IF}^{cal}=f_{IF}-{\mathrm{Mf}}_{RF}^l.$

Thus detect the phase error that removal cable 4 introduces, and at final test result alignment.

Being this device to be applied to 495GHz vector field measure system as shown in Figure 3, wherein radio frequency frequency is combined and local oscillator frequency is combined Frequency be respectively the microwave signal of 13.75GHz Yu 13.76GHz, after 36 frequencys multiplication, obtain the Terahertz of 495GHz Radiofrequency signal and the Terahertz local oscillation signal of 495.36GHz, after HEB frequency mixer is mixed, produce the intermediate-freuqncy signal of 360MHz.System System 10MHz reference signal by parametric mixer 1 produce, frequency microwave signal through removal cable 4 reflect after by parametric mixer 26 receive.The output signal of parametric mixer 26 is through duplexer 15 passage by capture card 12 together with 360MHz intermediate-freuqncy signal One gathers, and capture card 12 specifically uses NI5772R dual channel high speed A/D capture card.What capture card 12 collected is time-domain signal, After FFT, 360MHz intermediate-freuqncy signal, system 10MHz reference signal and the phase of mobile reflected signal can be respectively obtained Position, i.e. can obtain removal cable phase place through data process and change and calibrate.

Below being only the preferred embodiment of the present invention, protection scope of the present invention is not limited merely to above-described embodiment, All technical schemes belonged under thinking of the present invention belong to protection scope of the present invention.It should be pointed out that, for the art For those of ordinary skill, some improvements and modifications without departing from the principles of the present invention, should be regarded as the protection of the present invention Scope.

Claims (9)

1. one kind utilizes the device of removal cable phase place change in circulator calibration vector field measurement, it is characterised in that: include penetrating Again and again combine (1) and local oscillator frequency combines (2)；Radio frequency frequency is combined (1) and is connected with the first directional coupler (3), and the first directional coupler (3) is straight Go side is connected with removal cable (4), and coupled end is connected with parametric mixer；Removal cable (4) is connected to the port of circulator (7) One, the port two of circulator (7) is connected to the second directional coupler (9) by amplifier (8), the second directional coupler (9) Straight-through end is connected with radio frequency doubler (10), and coupled end is connected with the port three of circulator (7), and radio frequency doubler (10) is connected to Receiver (11)；The medium frequency output end of parametric mixer is connected to capture card (12)；Local oscillator frequency is combined (2) and is connected respectively by power splitter Being connected to local oscillator doubler (13) and parametric mixer, local oscillator doubler (13) is connected to receiver (11)；Receiver (11) passes through IF process module (14) is connected to capture card (12).

Utilizing the device of removal cable phase place change in circulator calibration vector field measurement the most as claimed in claim 1, it is special Levy and be: described first directional coupler (3) is dual directional coupler, and described parametric mixer includes parametric mixer one (5) With parametric mixer two (6), two coupled end of the first directional coupler (3) are mixed with parametric mixer one (5) and reference respectively Frequently device two (6) is connected.

Utilizing the device of removal cable phase place change in circulator calibration vector field measurement the most as claimed in claim 2, it is special Levy and be: the medium frequency output end of described parametric mixer one (5) is connected to capture card (12), described parametric mixer two (6) Medium frequency output end is connected with capture card (12) by duplexer (15).

Utilizing the device of removal cable phase place change in circulator calibration vector field measurement the most as claimed in claim 3, it is special Levy and be: described power splitter includes that the first power splitter (16) and the second power splitter (17), local oscillator frequency combine (2) by the first power splitter (16) being divided into two-way, a road is connected to local oscillator doubler (13), and the second power splitter (17) of separately leading up to is divided into again two-way, respectively It is connected with parametric mixer one (5) and parametric mixer two (6).

Utilizing the device of removal cable phase place change in circulator calibration vector field measurement the most as claimed in claim 4, it is special Levy and be: described capture card (12) is high-speed a/d capture card.

Utilizing the device of removal cable phase place change in circulator calibration vector field measurement the most as claimed in claim 4, it is special Levy and be: described receiver (11) includes HEB frequency mixer.

Utilizing the device of removal cable phase place change in circulator calibration vector field measurement the most as claimed in claim 4, it is special Levy and be: the coefficient of coup of described second directional coupler (9) is suitable with the amplification of amplifier (8).

8. one kind uses and utilizes removal cable phase in circulator calibration vector field measurement as according to any one of claim 4-7 The calibration steps of the device of position change, it is characterised in that including:

Radio frequency frequency combine (1) produce frequency microwave signal, local oscillator frequency combine (2) produce local oscillator microwave signal, frequency microwave signal and this After microwave signal of shaking is respectively through M frequency multiplication, being received machine (11) and produce intermediate-freuqncy signal, wherein M is the frequency multiplication of terahertz signal Number of times；

Frequency microwave signal flows into from the port one of circulator (7) through removal cable (4), fixed through amplifier (8) and second To bonder (9), the coupled end of the second directional coupler (9) flow through the port three of circulator (7), be re-introduced into removal cable (4), parametric mixer two (6) receive；

Parametric mixer one (5) exports system reference signal, parametric mixer two (6) output mobile reflected signal；Utilize duplex Intermediate-freuqncy signal is gathered together with mobile reflected signal by device (15) by capture card (12), and capture card (12) also acquisition system is with reference to letter Number；

Obtain phase information according to the signal that capture card (12) collects, calculate and calibrate the phase place that removal cable (4) is introduced Error.

Utilize the calibration of the device of removal cable phase place change in circulator calibration vector field measurement the most as claimed in claim 8 Method, it is characterised in that:

Radio frequency frequency combines (1) and local oscillator frequency combines the initial phase of (2) signal respectivelyAndThe phase place of system reference signal is:

$f_{ref}^0=f_{RF}^0-f_{LO}^0$

The electrical length of removal cable (4) isThe radiofrequency signal phase place entering parametric mixer two (6) is:

$f_{RF}^1=f_{RF}^0+2f_{RF}^l$

The phase place of parametric mixer two (6) intermediate frequency output is:

$f_{ref}^1=f_{RF}^0-f_{LO}^0+2f_{RF}^l$

Therefore the phase place through the change of removal cable (4) detected is:

$f_{RF}^l=(f_{ref}^1-f_{ref}^0)/2$

The intermediate frequency phase place detected is f_IF, then the intermediate frequency phase place after calibration is:

$f_{IF}^{cal}=f_{IF}-{\mathrm{Mf}}_{RF}^l.$