Active orientation structure for test and / or measurement system
By adopting active directional structure and fast switching transistors in vector network analyzers, the problems of high noise and low isolation of traditional VNAs in a wide frequency range are solved, and the low noise and high isolation effect of ultra-wideband is achieved.
Patent Information
- Application Number
- CN202411198533.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-01
- Filing Date
- 2024-08-29
- Publication Date
- 2025-06-03
AI Technical Summary
Traditional vector network analyzers (VNAs) have problems with high noise and low isolation when measured over a wide frequency range, and bandwidth limitations of passive orientation elements lead to limitations of narrowband systems.
Using an active directional structure, including a generator port, a DUT port, a measurement port and a reference port, the test, reflection and processing of the reference signal is realized through the first and second converters, and ultra-wideband operation is realized using a fast switching transistor.
Low noise and high port isolation operation in the ultra-wideband range are achieved, with better performance than traditional passive bridge structures.
Smart Images
Figure CN120085079A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an active directional structure for a test and / or measurement system, such as a vector network analyzer. The present invention also relates to a test and / or measurement system comprising such an active directional structure. Background Art
[0002] A vector network analyzer (VNA) is a measuring instrument that can be used to measure network parameters of an electrical network or a device under test (DUT). Such measurements are typically to be performed over a wide frequency range. In addition, for performing such measurements, a VNA typically requires internal components for separating and coupling out different forward and return signals from an internal signal path.
[0003] In a conventional VNA, this is typically achieved by a broadband system of passive directional elements (e.g., bridges) within the VNA. Although this method allows broadband coupling, due to the architecture of the bridge, the passive elements are inherently subject to high noise and low isolation (e.g., isolation between a generated signal and a reflected signal).
[0004] As an alternative, a narrowband system of passive directional elements (e.g., couplers) can be used. However, such a method is often affected by the passive bandwidth limitations of the passive directional elements. Summary of the Invention
[0005] Accordingly, it is an object to provide an active directional structure for a test and / or measurement system, such as a VNA, which avoids the above-mentioned drawbacks.
[0006] By the solution provided herein, the above object is achieved. Advantageous implementations of the present invention are further defined herein.
[0007] According to a first aspect, the present invention relates to an active directional structure for a test and / or measurement system. The active directional structure comprises: a generator port configured to receive a generator signal; a DUT port arranged for directly or indirectly connecting a device under test (DUT); a measurement port configured to output a measurement signal; and a reference port configured to output a reference signal. The active directional structure further comprises a first converter and a second converter.
[0008] The first converter is configured to: receive the generator signal at an input terminal connected to the generator port; generate a test signal based on the generator signal and output the test signal at a first output terminal connected to the DUT port; and generate the reference signal based on the generator signal and output the reference signal at a second output terminal connected to the reference port. The second converter is configured to: receive the test signal and the reflected signal from the DUT at a first input terminal; receive the reference signal at a second input terminal; and generate the measurement signal based on the test signal, the reflected signal, and the reference signal, and output the measurement signal at an output terminal connected to the measurement port. The first converter and / or the second converter includes respective transistor circuits.
[0009] This achieves the following advantages: providing an active directional structure that can operate in the ultra-wideband range, which is achieved in particular by using fast-switching transistors in at least one of its converters. At the same time, compared with a structure having a passive bridge / resistive bridge, this active directional structure has lower noise and higher port isolation.
[0010] The test and / or measurement system can be a measuring instrument, such as a vector network analyzer (VNA). The active directional structure can be an internal component of the VNA for combining, separating, and / or forwarding various RF signals (e.g., for measuring the network parameters of a DUT connected to the DUT port).
[0011] For example, the DUT can be directly connected to the DUT port. However, the DUT can also be connected to another port (e.g., a VNA port) on the housing of the test and / or measurement system, where the DUT port of the active directional structure is connected to the port through a signal line.
[0012] The generator signal, the reference signal, and the test signal can be respective RF signals (e.g., RF signals in a frequency range between DC and mmWave).
[0013] The generator signal can be a continuous wave (CW) signal generated by a signal generator connected to the generator port.
[0014] The test signal and / or the reference signal can be an amplified version of the generator signal. The test signal and the reference signal can be correlated with each other. For example, the reference signal can be the same as the test signal, or can be an inverted version of the test signal (e.g., the amplitudes of the two signals are equal, but the polarities are opposite), depending on the configuration of the first converter.
[0015] For example, only one of the first converter and the second converter includes a transistor structure, and the other converter includes only passive components, such as resistors. Alternatively, both the first converter and the second converter include respective transistor structures.
[0016] The first converter and the second converter may be respective converter structures or converter units.
[0017] In one embodiment, the first converter is a power splitter.
[0018] The power splitter may be configured to split a signal at a single-ended input into two output signals having the same phase and polarity. Additionally, the signal levels of the two output signals may be the same. In the case where the signal levels of the two output signals are different, the difference is known.
[0019] For example, the reference signal and the test signal output by the power splitter may correspond to the generator signal received by the power splitter, or may be an amplified version of the generator signal. For example, the reference signal and the test signal may have the same frequency, amplitude, and sign (i.e., the same polarity).
[0020] In one embodiment, the second converter is configured to calculate the difference between the combined test signal and the reflected signal received at the first input and the reference signal received at the second input, and output the measurement signal based on the difference.
[0021] Thus, the combined signal refers to the sum or superposition of two signals.
[0022] The measurement signal may correspond to the difference between the signals received at the first input and the second input of the second converter. This difference may correspond to the reflected signal from the DUT.
[0023] In one embodiment, the first converter is a single-ended to differential converter.
[0024] For example, the reference signal and the test signal may correspond to the generator signal or may be an amplified version of the generator signal, but may have opposite signs. For example, the reference signal and the test signal have the same frequency and amplitude, but opposite signs (e.g., they are signals with opposite polarities).
[0025] In one embodiment, the second converter is configured to calculate the sum of the combined test signal and the reflected signal received at the first input and the reference signal received at the second input, and output the measurement signal based on the sum.
[0026] The measurement signal can correspond to the sum of the signals received at the first input and the second input of the second converter. Since the polarities of the reference signal and the test signal are different, this sum can correspond to the reflected signal from the DUT.
[0027] In one embodiment, the active directional structure further includes: a first mixing device connected between the output of the second converter and the measurement port. This achieves the following advantage: the measurement signal can be down-converted to baseband for further processing.
[0028] In one embodiment, the active directional structure further includes: a second mixing device connected between the second output of the first converter and the reference port. This achieves the following advantage: the reference signal can be down-converted to baseband for further processing.
[0029] The first mixing device and / or the second mixing device includes at least one mixer connected to a local oscillator.
[0030] In one embodiment, the active directional structure further includes: a first attenuator unit connected between the first output of the first converter and the DUT port; and / or a second attenuator unit connected between the second output of the first converter and the reference port; and / or a third attenuator unit connected between the output of the second converter and the measurement port.
[0031] Therefore, the attenuator unit can be arranged before the corresponding mixing device.
[0032] The attenuator unit and / or the mixing device can be arranged within the active directional structure, for example, respectively before the DUT port, the measurement port, and the reference port.
[0033] In one embodiment, the active directional structure further includes: a fourth attenuator unit directly connected in front of the first input of the second converter; and / or a fifth attenuator unit directly connected in front of the second input of the second converter.
[0034] In one embodiment, the active directional structure further includes: an amplifier unit connected between the generator port and the input of the first converter. This achieves the following advantage: the generator signal can be pre-amplified to an appropriate signal level.
[0035] In one embodiment, the active directional structure is part of a chip or die. The chip can be a monolithic chip, which can be an internal component of a test and / or measurement system. For example, it can be arranged on the circuit board of a VNA.
[0036] The chip can be based on silicon-germanium technology. However, other technologies are also possible.
[0037] For example, the chip can include a mixing device and / or an attenuator unit.
[0038] According to a second aspect, the present invention relates to a test and / or measurement system, comprising: at least one active directional structure according to the first aspect of the present invention; a signal generator configured to generate the generator signal, wherein the output terminal of the signal generator is connected to the generator port of the active directional structure.
[0039] In one embodiment, the test and / or measurement system is a vector network analyzer (VNA).
[0040] In one embodiment, the test and / or measurement system further comprises: a first analog-to-digital converter unit (ADC unit) connected to the measurement port.
[0041] In one embodiment, the test and / or measurement system further comprises: a second analog-to-digital converter unit (ADC unit) connected to the reference port.
[0042] With the aid of the ADC unit, the measurement signal and the reference signal can be digitized for further processing by the VNA, for example for performing S-parameter characterization of the connected DUT based on these signals. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The above aspects and implementations are explained in the following description of embodiments with reference to the drawings:
[0044] Figure 1 A schematic diagram of an active directional structure according to one embodiment is shown;
[0045] Figure 2 A schematic diagram of an active directional structure according to one embodiment is shown;
[0046] Figure 2A A schematic diagram of an active directional structure according to one embodiment is shown;
[0047] Figure 3 A schematic diagram of an active directional structure according to one embodiment is shown;
[0048] Figure 4 A schematic diagram of an active directional structure according to one embodiment is shown;
[0049] Figure 5 Shows a schematic diagram of an active directional structure according to an embodiment;
[0050] Figure 6 Shows a schematic diagram of a test and / or measurement system according to an embodiment; and
[0051] Figure 7 Shows an implementation of an active directional structure according to an embodiment. Detailed Description
[0052] Figure 1 Shows a schematic diagram of an active directional structure 10 for a test and / or measurement system according to an embodiment.
[0053] The active directional structure 10 includes: a generator port P1 configured to receive a generator signal; a DUT port P2 arranged for direct or indirect connection to a device under test (DUT); a measurement port P3 configured to output a measurement signal; and a reference port P4 configured to output a reference signal.
[0054] The active directional structure 10 includes a first converter 11 configured to: receive a generator signal at an input terminal 11a connected to the generator port P1, generate a test signal based on the generator signal, output the test signal at a first output terminal 11b connected to the DUT port P2, generate a reference signal based on the generator signal, and output the reference signal at a second output terminal 11c connected to the reference port P4. The active directional structure 10 further includes a second converter 12 configured to: receive the test signal and a reflected signal from the device under test at a first input terminal 12b, receive the reference signal at a second input terminal 12c, generate a measurement signal based on the test signal, the reflected signal, and the reference signal, and output the measurement signal at an output terminal 12a connected to the measurement port P3.
[0055] The first converter 11 and / or the second converter 12 of the active directional structure 10 includes respective transistor circuits.
[0056] Thus, a connection between two ports refers to a connection suitable for forwarding an RF signal from one port to another (e.g., a connection via a signal routing line).
[0057] For example, the first converter 11 is an active element and the second converter 12 is a passive element, or vice versa. Alternatively, both the first converter 11 and the second converter 12 are active elements including respective transistor circuits.
[0058] The transistor circuit may be a circuit including one or more transistors (e.g., a transistor-based active circuit).
[0059] Due to the use of such active transistor-based circuits in at least one of the converters 11, 12, the active directional structure 10 can provide lower noise and higher port isolation than similar measurement systems using passive / resistive bridges. At the same time, the active directional structure 10 can operate over an ultra-wideband from DC to mmWave (millimeter wave).
[0060] The active directional structure 10 can be an internal component of a test and / or measurement system, such as a vector network analyzer (VNA).
[0061] The generator port P1 can be connected to a signal generator 21 configured to generate a generator signal, such as a generator signal in the form of a CW signal.
[0062] The DUT can be directly or indirectly connected to the DUT port P2. In Figure 1 the DUT impedance ZDUT is shown. The DUT can be a radio frequency device or component, such as a cable, filter, or attenuator.
[0063] The DUT port P2 can be arranged on the housing of the test and / or measurement system or can be connected to a port on the housing of the test and / or measurement system.
[0064] The input terminal 11a and output terminals 11b, 11c of the first converter 11, and the input terminals 12b, 12c and output terminal 12a of the second converter 12 can include any means for receiving and / or forwarding RF signals, such as ports, connectors, or nodes.
[0065] The first output terminal 11b of the first converter 11, the DUT port P2, and the first input terminal 12b of the second converter 12 can be connected by one or more signal lines. Similarly, the second output terminal 11c of the first converter 11, the reference port P4, and the second input terminal 12c of the second converter 12 can be connected by one or more signal lines.
[0066] The first converter 11 and the second converter 12 can form an active directional element (ADE) of the active directional structure 10.
[0067] When the generator signal is fed to the generator port P1, the active directional element (i.e., the first converter 11 and the second converter 12) can generate a test signal and forward it to the DUT port P2, and forward a reference signal to the reference port P4. The DUT connected at the DUT port P2 can reflect the incident wave of the test signal. This reflected wave can be forwarded to the measurement port P3 via the second converter 12.
[0068] In Figure 1In the example shown, the first converter is a power splitter.
[0069] Figure 1 The first converter 11 in Figure 1 can convert the generator signal from single-ended to a differential signal pair (a test signal and a reference signal). The test signal output from the first output terminal 11b and the reference signal output from the second output terminal 11c can be the same voltage signal Vi, especially a voltage signal Vi with the same sign (e.g., the same polarity) and phase. The power splitter can also generate a test signal and a reference signal with the same amplitude. If their amplitudes are different, this difference is known.
[0070] The test signal Vi can be forwarded from the first output terminal 11b to a DUT connected to the DUT port P2. In response, a reflected signal Vr can be received at the DUT port P2. The reflected signal Vr can be based on the reflection of the test signal Vi from the DUT (e.g., the DUT reflects a part of the test signal Vi). The first input terminal 12b of the second converter 12 can receive the combined (e.g., superimposed) test signal and reflected signal (Vi + Vr).
[0071] The reference signal (also Vi here) can be forwarded from the second output terminal 11c to the reference port P4 and the second input terminal 12c of the second converter 12. A reference impedance ZREF (e.g., 50 Ω) can be connected to the reference port P4.
[0072] The second converter 12 can be an active subtraction element. For example, the second converter 12 is configured to calculate the difference between the reference signal (Vi) received at the second input terminal 12c and the combined test signal and reflected signal (Vi + Vr) received at the first input terminal 12b. In other words, the second converter 12 can be configured to subtract the reference signal (Vi) from the combined test signal and reflected signal (Vi + Vr). The measurement signal can be the result of this subtraction, i.e.: (Vi + Vr) – Vi = Vr.
[0073] The second converter 12 can be configured to output the measurement signal to the measurement port P3.
[0074] Figure 2 An alternative implementation of the active directional element is shown, where the first converter is a single-ended to differential converter and the second converter is a summing element. For example, Figure 2 the first converter in Figure 2 is a single-ended to differential operational amplifier (opp-amp).
[0075] Figure 2The first converter 11 therein can convert the generator signal from single-ended to a differential signal pair. Thus, the test signal output from the first output terminal 11b and the reference signal output from the second output terminal 11c can be inverted voltage signals Vi with the same amplitude and phase but opposite signs (e.g., signals with different polarities). For example, the test signal is +Vi and the reference signal is -Vi.
[0076] The second converter 12 can be configured to calculate the sum between the reference signal (-Vi) received at the second input terminal 12c and the combined test signal and reflection signal (Vi + Vr) received at the first input terminal 12b. The measurement signal can be the result of this sum, i.e., (Vi + Vr) - Vi = Vr.
[0077] Figure 2A shows Figure 2 a schematic diagram of the active directional structure 10 shown in, where the corresponding attenuator units 44, 45 are directly connected in front of the first input terminal 12b and the second input terminal 12c of the second converter 12, respectively. Specifically, the attenuator units 44, 45 are arranged before the DUT port P2 and the reference port P4 (viewed from the second converter 12).
[0078] Such attenuator units 44, 45 can also be added to Figure 1 the active directional structure 10 shown in. In addition, only one of the attenuator units 44 and 45 can be added.
[0079] Figure 3 shows a schematic diagram of the active directional structure 10 according to an embodiment. Here, the first converter 11 and the second converter 12 are represented by the active directional element ADE. The first converter 11 and the second converter 12 can be configured as shown in any one of Figure 1 and Figure 2 shown in.
[0080] The active directional structure 10 can include a first mixing device 31 connected between the output terminal 12a of the second converter 12 and the measurement port P3, and / or a second mixing device 32 connected between the second output terminal 11c of the first converter 11 and the reference port P4.
[0081] The first mixing device 31 and / or the second mixing device 32 can include corresponding mixers connectable to the local oscillator LO.
[0082] The first mixing device 31 and the second mixing device 32 can be configured to down-convert the measurement signal or the reference signal to an intermediate frequency. For example, the mixing devices 31, 32 can down-convert these signals to baseband.
[0083] Figure 4Shows a schematic diagram of an active directional structure 10 according to another embodiment.
[0084] Figure 4 The active directional structure 10 in Figure 3 can be based on the structure 10 shown in
[0085] and includes additional attenuator units 41, 42, 43. For example, the first attenuator unit 41 is arranged in the signal path between the first output terminal 11b of the first converter 11 and the DUT port P2, the second attenuator unit 42 is arranged in the signal path between the second output terminal 11c of the first converter 11 and the reference port P4, and the third attenuator unit 43 is arranged in the signal path between the output terminal 12a of the second converter 12 and the measurement port P3.
[0086] Each of the attenuator units 41, 42, 43 can include a switchable attenuator block.
[0087] According to requirements, the active directional structure 10 can include one, two, or all of the first attenuator unit 41, the second attenuator unit 42, and the third attenuator unit 43. For example, the attenuator units 41, 42, 43 are arranged before the mixers of the respective mixing devices 31, 32.
[0088] The active directional structure 10 can also include any combination of the attenuator units 41, 42, 43 without including additional mixing devices 31, 32.
[0089] Figure 5 Shows a schematic diagram of an active directional structure 10 according to another embodiment. Here, the active directional structure 10 includes an additional amplifier unit 51 connected between the generator port P1 and the input terminal 11a of the first converter 11.
[0090] The amplifier unit 51 can be configured to amplify the generator signal before feeding the generator signal to the input terminal 11a of the first converter 11.
[0091] Figure 6 Shows a schematic diagram of a test and / or measurement system 60 according to one embodiment. For example, the test and / or measurement system 60 can be a VNA.
[0092] The test and / or measurement system 60 includes at least one active directional structure 10 as shown in any one of Figures 1 - 5 and a signal generator 21 configured to generate a generator signal. The signal generator 21, particularly the output terminal of the signal generator 21, is connected to the generator port P1 of the active directional structure 10.
[0093] As shown in Figure 6As shown, the test and / or measurement system 60 may include at least two active directional structures 10, where the generator port P1 of each structure 10 is connected to a signal generator 21, and the DUT port P2 of each structure 10 is connected to respective VNA ports 61, 62 via respective measurement paths 65, 66.
[0094] The DUT may be connected to the first VNA port 61 and the second VNA port 62.
[0095] Each active directional structure 10 may further include a first ADC unit 63 connected to the measurement port P3 and / or a second ADC unit 64 connected to the reference port P4.
[0096] The ADC units 63, 64 may be configured to digitize the respective measurement signals and reference signals output from ports P3, P4.
[0097] For example, additional elements (such as filters) may be arranged between the respective ADC units 63, 64 and ports P3, P4.
[0098] The test and / or measurement system may include a processing unit communicatively connected to the measurement port P3 and the reference port P4. The processing unit may receive and further process the digitized measurement signals and reference signals.
[0099] In this configuration, the VNA 60 may use the DUT to perform network parameter (e.g., S-parameter) measurements.
[0100] The active directional structure 10 may be designed in the form of a monolithic (single) chip of the test and / or measurement system 60. For example, Figure 5 all the elements shown (especially mixers 31, 32 and attenuator units 41 - 43) may be integrated in the chip.
[0101] The chip may include active directional elements (a first converter and a second converter), optional mixing devices 31, 32 and optional attenuator units 41 - 43. For example, the chip may be based on silicon germanium technology or other technologies. In this way, the size / footprint of the structure 10 and the PCB complexity of the system 60 can be significantly reduced. At the same time, performance parameters such as bandwidth, directivity and temperature stability can also be improved.
[0102] Figure 7 A possible implementation of the active directional structure 10 according to one embodiment is shown.
[0103] In Figure 7 the structure 10 shown, the signal Vi received at the generator port P1 may be used to generate a differential current signal through a transconductance amplifier (TAA) 81. The TAA 81 may form a differential current source (e.g., according to Figure 2in the first converter 11). For example, a differential transistor pair can be used as the TAA 81.
[0104] One side of the differential current source 81 can be connected to the DUT port P2. In addition, the termination resistor R can also be connected to the port P2. Thus, the impedance at the port P2 can be R. Typically, R is 50 ohms.
[0105] Externally, a DUT with an unknown impedance Zdut to be measured by a test and / or measurement system can be connected to the DUT port P2.
[0106] The other side of the differential current source 81 can also be connected to the termination resistor R, but instead of the unknown impedance Zdut, this side can also be loaded by a known and exact reference resistor R.
[0107] Instead of connecting the other end of the termination resistor to ground (or to a constant power supply voltage), a device for measuring the sum of the currents through the two termination resistors can be used (e.g., according to Figure 2 in the second converter 12).
[0108] As Figure 7 shown, the active directional structure 10 can include an ideal type of second-generation current conveyor (ccII) as such a device. The function of this idealized element is to force the voltage applied to the terminal Y to be applied to the terminal X. In addition, the current flowing into the terminal X is transferred to the high-impedance output terminal Z. In particular, the ccII can be implemented by a single transistor or an operational amplifier feedback circuit.
[0109] Assuming that Zdut is exactly 50 ohms, the differential current can cause a voltage signal Vi to appear at the port P2 and a voltage signal -Vi (same amplitude but opposite polarity) to appear at the reference resistor on the other side of the bridge. The currents flowing through the termination resistors can both have an amplitude of Vi / R but flow in opposite directions. Thus, the sum of the two currents flowing through the ccII to the port P3 is zero.
[0110] In the case where Zdut is not exactly 50 ohms, in addition to Vi, a reflected voltage Vr will appear at the port P2. In this case, the sum of the currents through the two termination resistors is Vr / R, which makes the voltage at the port P3 the reflected voltage Vr. This allows the reflected voltage Vr to be measured at the measurement port P3.
[0111] Except that one side of the bridge is loaded by Zdut and the other side is loaded by R, the structure 10 can be completely symmetric. In an integrated circuit implementation, excellent matching can be achieved between the two sides, which can translate into excellent directivity.
[0112] Rather than directly measuring the sum of the currents through two terminal resistors, the current through each resistor can be measured separately and then the two currents added together.
[0113] As Figures 1 - 7 shown in any of them, the active directional structure 10 can be designed as a small broadband directional circuit for a network analyzer port. The structure 10 can be fully integrated on a monolithic chip.
[0114] Compared with a circulator design based on a balun (active or passive), the active directional structure 10 has the following advantages: The entire signal power generated by the circuit can be transmitted to the DUT. This can reduce the need for additional (off-chip) passive components for attenuating the signal.
[0115] Compared with a possible active circulator implementation based on operational amplifiers, the active directional structure 10 can operate very fast because it can include only a few transistors operating in a feed-forward configuration.
[0116] The active directional structure 10 can also achieve very high directivity because it can be based on the matching between two structurally identical signal paths (e.g., see Figures 1 - 2 and Figure 7 ).
[0117] In addition to its use in the VNA discussed above, the structure 10 can also be used to separate the transmit and receive paths in a wireless communication or radar device where the two paths share a common antenna.
Claims
1. An active directional structure (10) for use in a test and / or measurement system (60), comprising: a generator port (P1) configured to receive a generator signal; a DUT port (P2), the DUT port being arranged for direct or indirect connection to a device under test DUT; a measurement port (P3), the measurement port being configured to output a measurement signal; a reference port (P4), the reference port being configured to output a reference signal; A first converter (11), wherein the first converter is configured to: - receiving said generator signal at an input (11a) connected to said generator port (P1), - generating a test signal based on the generator signal and outputting the test signal at a first output terminal (11b) connected to the DUT port (P2), and - generating the reference signal based on the generator signal and outputting the reference signal at a second output terminal (11c) connected to the reference port (P4); as well as A second converter (12), the second converter being configured to: - receiving the test signal and the reflected signal from the DUT at a first input terminal (12b), - receiving said reference signal at a second input (12c), and - generating the measurement signal based on the test signal, the reflected signal and the reference signal, and outputting the measurement signal at an output terminal (12a) connected to the measurement port (P3); The first converter (11) and / or the second converter (12) include respective transistor circuits.
2. The active directional structure (10) according to claim 1, wherein: The first converter (11) is a power divider.
3. The active directional structure (10) according to claim 2, wherein: The second converter (12) is configured to calculate a difference between the combined test signal and reflected signal received at the first input (12b) and the reference signal received at the second input (12c), and to output the measurement signal based on the difference.
4. The active directional structure (10) according to claim 1, wherein: The first converter (11) is a single-ended to differential converter.
5. The active directional structure (10) according to claim 4, wherein: The second converter (12) is configured to calculate the sum of the combined test signal and reflected signal received at the first input (12b) and the reference signal received at the second input (12c), and output the measurement signal based on the sum.
6. The active directional structure (10) according to any one of claims 1 to 5, further comprising: A first frequency mixing device (31) is connected between the output end (12a) of the second converter (12) and the measurement port (P3).
7. The active directional structure (10) according to any one of claims 1 to 6, further comprising: A second frequency mixing device (32) is connected between the second output terminal (11c) of the first converter (11) and the reference port (P4).
8. The active directional structure (10) according to any one of claims 1 to 7, further comprising: a first attenuator unit (41), the first attenuator unit being connected between the first output terminal (11b) of the first converter (11) and the DUT port (P2); and / or a second attenuator unit (42), the second attenuator unit being connected between the second output terminal (11c) of the first converter (11) and the reference port (P4); and / or A third attenuator unit (43) is connected between the output end (12a) of the second converter (12) and the measurement port (P3).
9. The active directional structure (10) according to any one of claims 1 to 8, further comprising: a fourth attenuator unit (44), the fourth attenuator unit being directly connected before the first input terminal (12b) of the second converter (12); and / or A fifth attenuator unit (45) is connected directly before the second input terminal (12c) of the second converter (12).
10. The active directional structure (10) according to any one of claims 1 to 9, further comprising: An amplifier unit (51) is connected between the generator port (P1) and an input terminal (11a) of the first converter (11).
11. The active directional structure (10) according to any one of claims 1 to 10, wherein: The active directional structure is part of the chip.
12. A testing and / or measuring system (60), comprising: At least one active directional structure (10) according to any one of claims 1 to 11; A signal generator (21) is configured to generate the generator signal, wherein an output end of the signal generator (21) is connected to the generator port (P1) of the active directional structure (10).
13. The test and / or measurement system (60) according to claim 12, wherein: The test and / or measurement system (60) is a vector network analyzer.
14. The test and / or measurement system (60) according to claim 12 or 13, further comprising: A first analog-to-digital converter unit (63) is connected to the measurement port (P3).
15. The test and / or measurement system (60) according to any one of claims 12 to 14, further comprising: A second analog-to-digital converter unit (64) is connected to the reference port (P4).