阅读说明：本技术 一种无参考接收机的矢量网络分析仪 (Vector network analyzer of non-reference receiver ) 是由 高博 童玲 宫珣 王培丞 张坤 林明维 于 2021-08-23 设计创作，主要内容包括：本发明公开了一种无参考接收机矢量网络分析仪,其架构中不需要参考接收机；在进行散射参数测量时,被测件的反射信号经耦合器分离后,由反射信号接收机测量其幅相信息,同时通过被测件的传输信号的幅相信息则由传输信号接收机来测量；在整个校准和测量过程中,激励源的幅度和相位并不需要已知,仅用一个幅度和相位未知的量来代替；在校准和数据处理过程中,利用误差项和散射参数均为接收机的测量值与激励源的比值这一特点,可以将未知激励源的影响完全消除,以实现被测件散射参数的准确测量。(The invention discloses a reference-free receiver vector network analyzer, which does not need a reference receiver in the framework; when scattering parameter measurement is carried out, after a reflected signal of a measured piece is separated by the coupler, the amplitude-phase information of the reflected signal is measured by the reflected signal receiver, and meanwhile, the amplitude-phase information of a transmission signal passing through the measured piece is measured by the transmission signal receiver; the amplitude and phase of the excitation source need not be known throughout the calibration and measurement process, but instead are simply an unknown quantity of amplitude and phase; in the calibration and data processing processes, the characteristic that an error term and scattering parameters are the ratio of the measured value of the receiver to the excitation source is utilized, so that the influence of the unknown excitation source can be completely eliminated, and the scattering parameters of the measured piece can be accurately measured.)

1. A reference-receiver-less vector network analyzer, comprising:

the vector network analyzer without the reference receiver omits a reference receiver for monitoring the amplitude and the phase of an excitation signal in the traditional vector network analyzer by introducing a phase repeatable signal source and a corresponding calibration and data processing method, and can finish the accurate measurement of scattering parameters only by reserving a reflection and transmission signal measurement receiver;

the phase repeatable signal source comprises a phase repeatable radio frequency source and a phase repeatable local oscillator source. During frequency sweeping measurement, a radio frequency source with repeatable phases generates radio frequency signals with repeatable phases as excitation signals of a vector network analyzer, and a local oscillation source with repeatable phases generates local oscillation signals with repeatable phases; the introduction of the phase repeatable source ensures the amplitude-phase consistency of the signals of the vector network analyzer in the calibration and measurement processes.

2. The vector network analyzer without the reference receiver of claim 1, wherein the vector network analyzer does not need a reference receiver in its structure, and when the scattering parameter measurement is performed, the reflected signal of the tested piece is separated by the coupler, and then the amplitude and phase information of the reflected signal is measured by the reflected signal receiver, and meanwhile, the amplitude and phase information of the transmitted signal passing through the tested piece is measured by the transmitted signal receiver; because there is no reference receiver, the final scattering parameters are acquired by using the characteristics of the phase repeatable source and combining the data of the corresponding calibration process.

3. The non-reference receiver vector network analyzer according to claim 1, wherein a signal source with phase repeatable characteristics is used as an excitation source of the vector network analyzer and a local oscillator of a receiver;

the phase repeatable excitation source ensures that the amplitude and phase value of each frequency point of the excitation signal of the vector network analyzer are kept unchanged in the process of multiple frequency sweeps of calibration and measurement;

the phase repeatable local oscillation source ensures that the phase of the obtained intermediate frequency signal is not influenced by the phase change of the local oscillation signal after the measurement receiver carries out down-conversion on the measured signal.

4. The referenceless receiver vector network analyzer according to claim 1, wherein the magnitude and phase of the excitation source need not be known throughout the calibration and measurement procedure, but instead are replaced by an unknown magnitude and phase quantity; in the data processing process, the characteristic that the error term and the scattering parameter are the ratio of the measured value of the receiver to the excitation source is utilized, so that the influence of the unknown excitation source can be completely eliminated, and the scattering parameter of the measured piece can be accurately measured.

Technical Field

The invention belongs to the technical field of electronic measuring instruments, and particularly relates to a vector network analyzer without a reference receiver.

Background

The vector network analysis technology is widely applied to the precise measurement of characteristic parameters of microwave chips, devices, modules, systems and the like, is an essential measuring instrument in the research and development processes of systems such as communication, radar, remote sensing and the like, and has wide application field and huge market space.

The system architecture of the conventional vector network analyzer is shown in fig. 1 (taking a dual-port vector network analyzer as an example), two reference receivers R1 and R2 are used for measuring excitation signals, a receiver A and a receiver B are used for measuring reflection and transmission signals, and the reference receiver and the measurement receiver must work together to be able to obtain the scattering parameter S of a measured piece through a ratio_11M、S_21M、S_12MAnd S_22MThe method specifically comprises the following steps:

where the symbols A, B, R1 and R2 are used to represent the magnitude and phase values of the measured signals for the receivers A, B, R1 and R2, respectively. The scattering parameters also include system errors inside the vector network analyzer, and the system errors can be eliminated through calibration so as to accurately obtain the scattering parameters of the measured piece.

Since the vector network analyzer needs to operate in a very wide frequency band, the receiver therein must be capable of realizing ultra-wideband frequency conversion vector reception in a very wide frequency band. This results in a very expensive receiver inside the vector network analyzer, which makes the price of the whole vector network analyzer high, and severely restricts the application and popularization and the small portable design of the vector network analyzer.

Disclosure of Invention

The invention aims to solve the problems of high cost and large volume of the conventional vector network analyzer, and provides a vector network analyzer without a reference receiver, which can effectively reduce the number of receivers required in the vector network analyzer, simplify a radio frequency system of the vector network analyzer, greatly reduce the hardware cost of the vector network analyzer, reduce the volume of the vector network analyzer and provide a new solution for the economic and portable vector network analyzer.

In order to achieve the above object, the present invention provides a vector network analyzer without a reference receiver, which is characterized in that:

the vector network analyzer without the reference receiver omits a reference receiver for monitoring the amplitude and the phase of an excitation signal in the traditional vector network analyzer by introducing a phase repeatable signal source and a corresponding calibration and data processing method, and can finish accurate measurement on scattering parameters by only retaining a reflection and transmission signal measurement receiver.

The phase repeatable signal source comprises a phase repeatable radio frequency source and a phase repeatable local oscillator source. During frequency sweep measurement, a radio frequency source with repeatable phase generates a radio frequency signal with repeatable phase as an excitation signal of a vector network analyzer, and a local oscillation source with repeatable phase generates a local oscillation signal with repeatable phase. The introduction of the phase repeatable source ensures the amplitude-phase consistency of the signals of the vector network analyzer in the calibration and measurement processes.

The object of the invention is thus achieved.

The vector network analyzer without the reference receiver does not need the reference receiver in the structure. When the scattering parameter is measured, the reflected signal of the measured piece is separated by the coupler, the amplitude and phase information of the reflected signal is measured by the reflected signal receiver, and meanwhile, the amplitude and phase information of the transmission signal passing through the measured piece is measured by the transmission signal receiver. The amplitude and phase of the excitation source need not be known throughout the calibration and measurement process, but instead can be replaced by an unknown quantity of amplitude and phase. In the calibration and data processing processes, the characteristic that an error term and scattering parameters are the ratio of the measured value of the receiver to the excitation source is utilized, so that the influence of the unknown excitation source can be completely eliminated, and the scattering parameters of the measured piece can be accurately measured.

The invention can bring the following beneficial effects:

(1) the invention utilizes the signal source with repeatable phase, removes the reference receiver of the traditional vector network analyzer, reduces the cost and the volume, and has great application value in the field of economic and portable vector network analyzers;

(2) the invention has the advantages of reducing cost and volume, having equivalent measurement precision to the traditional vector network analyzer and realizing accurate acquisition of scattering parameters of the measured piece.

Drawings

FIG. 1 is an architecture of a conventional vector network analyzer;

FIG. 2 is an architecture of a reference-free receiver vector network analyzer of the present invention;

FIG. 3 is a structure of a measurement receiver;

FIG. 4 is the magnitude of S11 for the uncalibrated, calibrated, and true values;

FIG. 5 is the S11 phase with no calibration values;

FIG. 6 is the S11 phase for the calibration and actual values

FIG. 7 is the magnitude of S21 for the uncalibrated, calibrated, and true values;

FIG. 8 is the S21 phase with no calibration values;

fig. 9 is the S21 phase for the calibration value and the actual value.

Detailed Description

The following description of the embodiments of the present invention is provided in order to better understand the present invention for those skilled in the art with reference to the accompanying drawings. It is to be expressly noted that in the following description, a detailed description of known functions and designs will be omitted when it may obscure the subject matter of the present invention.

Examples

Fig. 2 is an architecture diagram of a reference-free receiver vector network analyzer according to the present invention (the embodiment takes a 2-port vector network analyzer as an example, and the present technology is also applicable to vector network analyzers with other port numbers and architectures).

In this embodiment, the vector network analyzer without a reference receiver includes: a signal source with repeatable phase, a radio frequency switch, a coupler and a measuring receiver;

the phase repeatable signal source comprises a phase repeatable radio frequency source and a phase repeatable local oscillation source, the phase repeatable radio frequency source generates a phase repeatable radio frequency signal to serve as an excitation signal of the vector network analyzer during frequency sweeping measurement, and the phase repeatable local oscillation source generates a phase repeatable local oscillation signal; in this embodiment, the phase of the excitation signal is repeatable and the amplitude is stable during multiple frequency sweep measurements, and can be represented as an unknown fixed value S.

The radio frequency switch is used for selecting a channel (a channel 1 and a channel 2) through which an excitation signal flows and an output port (a port 1 and a port 2);

when the excitation signal output by the port of the vector network analyzer acts on the device to be tested, one part of the signal is reflected, and the other part of the signal is transmitted to other ports of the vector network analyzer after passing through the device to be tested;

the coupler couples the reflected signal and the transmission signal to corresponding measurement receivers;

the measurement receiver comprises a receiver a and a receiver B for measuring the amplitude and phase of the signal. As shown in fig. 3, each of the receiver a and the receiver B includes a mixer, an analog intermediate frequency processing module, an analog-to-digital converter, and a digital intermediate frequency processing module. The measured signal is input into a frequency mixer to be mixed with a local oscillation signal generated by a local oscillation source with repeatable phase, the difference frequency of the measured signal and the local oscillation signal is reserved and amplified by an analog intermediate frequency processing module, and the difference frequency is digitized by an analog-to-digital converter and is sent into a digital intermediate frequency processing module to measure the amplitude and the phase;

as shown in fig. 2, when an input signal passes through the rf switch selection channel 1 for forward measurement, the input signal is applied to a device under test through the port 1 of the vector network analyzer, a part of the input signal will be reflected back by the device under test and enter the measurement receiver a through the coupler of the channel 1, and the signal measured by the measurement receiver a is a_M(ii) a Another part will be transmitted from the device under test and enter the measurement receiver B through the coupler of channel 2, and the signal measured by the measurement receiver B is B_M；

When the input signal passes through the radio frequency switch selection channel 2 for backward measurement, the input signal is applied to the device to be tested through the port 2 of the vector network analyzer, a part of the input signal is reflected back by the device to be tested,enters a measurement receiver B through a coupler of a channel 2, and the signal measured by the measurement receiver B is B'_MThe other part will be transmitted from the device under test and enter the measurement receiver A through the coupler of channel 1, and the signal measured by the measurement receiver A is a'_M(ii) a So far, the network parameters S of the tested device are obtained through measurement_11M、S_21M、S_12MAnd S_22MCan be expressed as:

wherein, S represents an excitation signal, and is a parameter to be calibrated and eliminated.

The network parameter of the tested device has an unknown fixed value S, and meanwhile, a system error also exists in the non-reference receiver, and the S and the system error need to be eliminated through calibration, so that the real network parameter is obtained.

Due to the introduction of a phase repeatable signal source, although the output S of the signal source is unknown, since both the amplitude and the phase of the signal source can be repeated, the S and the systematic error can be eliminated by calibrating with the following method to obtain the real network parameters, specifically including the following steps:

(1) connecting an Open calibration piece to a port 1 of a vector network analyzer, selecting a channel 1 by a radio frequency switch to obtain data a of a receiver A_O；

(2) Connecting the Short calibration piece to port 1 of the vector network analyzer, selecting channel 1 by the radio frequency switch to obtain data a of the receiver A_S；

(3) Connecting the Load calibration part on a port 1 of the vector network analyzer, selecting a channel 1 by a radio frequency switch to obtain data a of the receiver A_LData B of B receiver_L；

(4) Connecting an Open calibration piece to a port 2 of the vector network analyzer, selecting a channel 2 by a radio frequency switch to obtain data B 'of a receiver B'_O；

(5) The Short calibration piece is connected to the port 2 of the vector network analyzer, the radio frequency switch selects the channel 2,obtaining data B 'of a B receiver'_S；

(6) Connecting the Load calibration piece to a port 2 of the vector network analyzer, selecting a channel 2 by a radio frequency switch to obtain data a 'of the receiver A'_LData B 'of B receiver'_L；

(7) Directly connecting a port 1 and a port 2 of the vector network analyzer to a Thru calibration piece, and obtaining data a of an A receiver when a radio frequency switch selects a channel 1_TData B of B receiver_T(ii) a When the radio frequency switch selects the channel 2, the data a 'of the A receiver is obtained'_TData B 'of B receiver'_T；

(8) Connecting the device to be tested to the port 1 and the port 2 of the vector network analyzer, and obtaining data a of the A receiver when the radio frequency switch selects the channel 1_MData B of B receiver_M(ii) a When the radio frequency switch selects the channel 2, the data a 'of the A receiver is obtained'_MData B 'of B receiver'_M；

(9) Calculating the real network parameters of the tested device through the measurement and calibration data obtained in the steps (1) to (8):

wherein:

forward measured coupler directivity error:

cross talk error between channels measured forward:

reflection tracking error of forward measurement:

forward measured transmission tracking error:

source mismatch error of forward measurement:

forward measured load mismatch error:

coupler directivity error measured backwards:

crosstalk error between channels measured backwards:

backward measured reflection tracking error:

transmission tracking error of backward measurement:

source mismatch error of backward measurement:

load mismatch error measured backwards:

it can be seen from the above formula that the scattering parameters of the device obtained after calibration have no relation with the unknown fixed value S representing the source, and the system errors of the reference-free receiver vector network analyzer are eliminated during the processing, so that the reference-free receiver vector network analyzer and the calibration and data processing method thereof of the present invention can accurately obtain the scattering parameters of the measured device.

Examples of the invention

In this embodiment, according to the architecture shown in fig. 2, a specific non-reference receiver vector network analyzer is implemented by using a phase repeatable source with an output frequency range (230MHz-3400 MHz).

The measurement results of the vector network analyzer without the reference receiver on the amplitude and the phase of scattering parameters S11 and S21 of a measured piece are shown in FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8 and FIG. 9. In the figure, the uncalibrated value refers to a direct measurement value of a receiver, the calibrated value is a measurement result obtained after the calibration and data processing method provided by the invention is carried out, and the actual value is a measurement result obtained by using a traditional commercial vector network analyzer. As can be seen from the figure, the amplitude and the phase of the scattering parameter obtained by the non-reference receiver vector network analyzer are almost completely consistent with the value measured by the traditional commercial vector network analyzer, which proves that the invention can effectively realize the accurate measurement of the scattering parameter of the measured piece while reducing the number of receivers.

Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all matters of the invention which utilize the inventive concepts are protected.