Method and measuring device for determining antenna factor of monopole antenna

Abstract

The invention discloses a method and a measuring device for determining an antenna factor of a monopole antenna. The invention relates to a method for determining an antenna factor of a monopole antenna. A universal artificial antenna is provided, and the coupling capacitance thereof is determined. The matching device is connected with the universal artificial antenna, and scattering parameters associated with the universal artificial antenna are measured. A calibration adapter replaces a universal artificial antenna, where scattering parameters associated with the calibration adapter are measured. An input capacitance of the matching device is determined. The monopole antenna is connected with the matching device and the universal artificial antenna, and scattering parameters associated with the universal artificial antenna and scattering parameters associated with the calibration adapter are measured. The calibration adapter replaces a universal artificial antenna. The capacitance of the monopole antenna is calculated. The antenna factor is determined based on a capacitance of the monopole antenna, a coupling capacitance of the universal artificial antenna, and an input capacitance of the matching device. A measuring device is shown.

Description

Technical Field

[0001] Embodiments of the present invention relate to a method for determining the antenna factor of a monopole antenna. Additionally, embodiments of the present invention relate to a measuring apparatus for determining the antenna factor of a monopole antenna. Background Technology

[0002] Monopole antennas are particularly useful for radiated emission measurements. The accuracy of monopole antenna calibration plays a crucial role in many fields, such as electromagnetic compatibility testing and EMC testing. Therefore, it is necessary to determine the antenna factor and calibrate the monopole antenna accordingly.

[0003] In the prior art, many methods are known for determining the antenna factor of a monopole antenna. One of the most commonly used methods for determining the antenna factor and calibrating a monopole antenna is the Equivalent Capacitor Substitution Method (ECSM). In this method, the monopole antenna is calibrated using an artificial antenna with a capacitor having a self-capacitance equal to that of the monopole antenna. The monopole antenna is thus replaced by the capacitor. The capacitance of the monopole antenna is then calculated according to the formula in DIN EN 55016-1-6.

[0004] However, for determining the antenna factor using the ECSM method, it is important that the artificial antenna is matched to the monopole antenna, or more precisely, that the capacitor of the artificial antenna has the same capacitance as that of the monopole antenna. Furthermore, the capacitance of the artificial antenna's capacitor must be known in advance in order to determine the antenna factor of the monopole antenna.

[0005] Another drawback of ECSM is that if the monopole antenna is not directly mounted on the ground, but rather at a certain distance from the ground, its ability to correct the effective height of the monopole antenna can only reach a limited extent.

[0006] Therefore, an improved method is needed to calculate the antenna factor of a monopole antenna and to calibrate the monopole antenna accordingly. Summary of the Invention

[0007] The following summary of the invention is intended to present, in a simplified form, the different concepts that are further described in detail in the detailed description provided below. This summary is not intended to represent the essential features of the invention, nor should it be used to assist in defining the scope of the claimed subject matter.

[0008] Embodiments of the present invention provide a method for determining the antenna factor of a monopole antenna. The method includes the following steps:

[0009] - Provide a universal artificial antenna and determine the coupling capacitance of the universal artificial antenna in the first measurement setup;

[0010] - Provide a matching device, connect the matching device to a universal artificial antenna to obtain a second measurement setting, and measure the scattering parameters associated with the universal artificial antenna in the second measurement setting.

[0011] - Provides a calibration adapter to connect the matching device, allowing the calibration adapter to replace the general-purpose artificial antenna, thereby obtaining a third measurement setting and measuring the scattering parameters associated with the calibration adapter in the third measurement setting.

[0012] - Use the ratio of the scattering parameters associated with the general artificial antenna in the second measurement setting and the scattering parameters associated with the calibration adapter in the third measurement setting to determine the input capacitance of the matched device;

[0013] - Provide a monopole antenna, connect the monopole antenna to a matching device and a universal artificial antenna to obtain a fourth measurement setting, and measure the scattering parameters associated with the universal artificial antenna in the fourth measurement setting;

[0014] - Provides a calibration adapter to connect the monopole antenna to the matching device and the calibration adapter, so that the calibration adapter replaces the general artificial antenna, thereby obtaining a fifth measurement setting and measuring the scattering parameters associated with the calibration adapter in the fifth measurement setting;

[0015] The capacitance of the monopole antenna is determined based on the coupling capacitance of the general-purpose artificial antenna, the input capacitance of the matching device, and the ratio of the scattering parameters associated with the general-purpose artificial antenna in the fourth measurement setting to the scattering parameters associated with the calibration adapter in the fifth measurement setting; and

[0016] The antenna factor of a monopole antenna is determined based on the capacitance of the monopole antenna, the coupling capacitance of a general artificial antenna, and the input capacitance of the matching device.

[0017] Furthermore, embodiments of the present invention provide a measuring apparatus for determining the antenna factor of a monopole antenna. This measuring apparatus has different measuring setups, wherein the measuring apparatus includes a universal artificial antenna, a calibration adapter, a matching device, a monopole antenna, and a network analyzer, which can be arranged differently to obtain different measuring settings.

[0018] In the first measurement setup used to determine the capacitance of the universal artificial antenna, the universal artificial antenna is coupled to the calibration adapter.

[0019] In a second measurement setup for measuring scattering parameters associated with a general-purpose artificial antenna, a matching device is coupled to the general-purpose artificial antenna, wherein the matching device and the artificial antenna are coupled to a network analyzer.

[0020] In a third measurement setup used to measure scattering parameters associated with the calibration adapter, a matching device is coupled to the calibration adapter, and both the matching device and the calibration adapter are coupled to a network analyzer.

[0021] In the fourth measurement setup for measuring scattering parameters associated with a general artificial antenna, a matching device is coupled to a monopole antenna, wherein the general artificial antenna is coupled to the monopole antenna, and wherein the general artificial antenna and the matching device are coupled to a network analyzer.

[0022] In the fifth measurement setup for measuring scattering parameters associated with the calibration adapter, a matching device is coupled to a monopole antenna, a calibration adapter is coupled to a monopole antenna, and both the calibration adapter and the matching device are coupled to a network analyzer.

[0023] To determine the different scattering parameters, a total of five measurement settings are required. Based on these scattering parameters, different capacitances can be calculated, thereby ultimately determining the antenna factor of the monopole antenna and calibrating the monopole antenna accordingly.

[0024] Hardware may include, in particular, CPUs, GPUs, FPGAs, ASICs, or other types of electronic circuit systems.

[0025] In this context, the term "connecting A and B" is understood to mean providing a conductive connection between A and B, such that signal transmission between A and B via an electrical conductor can be established, for example, via a line, cable, or wire.

[0026] Similarly, the term "connection" is understood to mean a conductive connection via an electrical conductor, especially without obstructions, such as a continuous electrical conductor.

[0027] The term “coupled to” is understood to mean a conductive connection via an electrical conductor, and therefore it is synonymous with the term “connected to”.

[0028] Furthermore, the term "general-purpose artificial antenna" is understood to refer to any type of artificial antenna that does not necessarily need to be tuned to a monopole antenna. Specifically, the resistor of a general-purpose artificial antenna does not necessarily need to be equal to the self-capacitance of a monopole antenna.

[0029] Furthermore, the term "monopol antenna" is understood to refer to monopol antennas of various shapes, such as poles of a specific length or height and / or a specific diameter, or any other type of monopol antenna. A monopol antenna can be mounted on the ground or on a grounding plate away from the ground. If the monopol antenna is mounted on a grounding plate away from the ground, it must be grounded via a suitable grounding wire.

[0030] The "scattering parameters" are known and describe the electrical behavior of a linear electrical network under various steady-state stimuli from an electrical signal, i.e., the ratio of incident to reflected waves. For example, the scattering parameters (S-parameters) of a two-port network have the following general description: S 11 It is the input port voltage reflection coefficient, S 12 It is the reverse voltage gain, S 21 It is the forward voltage gain, and S 22 It is the output voltage reflection coefficient.

[0031] The phrase “measuring scattering parameters” is understood to mean that the scattering parameters are determined based on the measured parameters, such as those based on the incident and reflected waves.

[0032] The method according to the invention is based on the idea that the antenna factor of a monopole antenna can be calculated in several steps using different measurement settings (also called measurement apparatus), wherein the calculation can be attributed (only) to scattering parameters measured in the different measurement settings. Depending on the measurement settings, the corresponding measured scattering parameters can be used to determine the capacitance of the monopole antenna, the input capacitance of the matching device, and / or the coupling capacitance of a general artificial antenna, wherein these parameters are taken into account when determining the antenna factor. In other words, the antenna factor is calculated and the monopole antenna is calibrated using directly measured scattering parameters or values ​​calculated based on measured scattering parameters, such as the input capacitance of the matching device and / or the capacitance of the monopole antenna.

[0033] The method of this invention has the advantage that the universal artificial antenna does not need to be matched with a monopole antenna, thus producing a universal artificial antenna that can be used to calibrate various monopole antennas. Furthermore, the capacitance of the universal artificial antenna is independent of characteristics such as the diameter or length of the monopole antenna.

[0034] As mentioned above, the calculation is based on scattering parameters, resulting in less uncertainty in the antenna factor calculation. Therefore, the antenna factor can be determined for different locations, such as different heights relative to the ground.

[0035] Furthermore, this method can be used to determine the capacitance of a monopole antenna's pole and to determine the antenna factor for different heights of the monopole antenna.

[0036] Typically, the corresponding measurements, namely the measurement of scattering parameters, can be performed using a network analyzer, especially in different measurement settings.

[0037] According to one aspect of the invention, a first measurement setup is obtained by coupling a universal artificial antenna to a calibration adapter, and the coupling capacitance of the universal artificial antenna is determined by measuring the scattering parameters associated with the universal artificial antenna coupled to the calibration adapter.

[0038] Therefore, the coupling capacitance of the universal artificial antenna is based on only one measurement, namely the scattering parameters of the universal artificial antenna coupled to the calibration adapter, in the first measurement setting.

[0039] In the following text, coupling capacitance refers to the capacitive coupling of general artificial antennas with respect to electromagnetic coupling, particularly the transfer of energy within an electrical network or between remote networks by means of displacement currents between nodes induced by an electric field.

[0040] Scattering parameters are measured using a network analyzer connected to both the universal artificial antenna and the calibration adapter.

[0041] The scattering parameter associated with the universal artificial antenna coupled to the calibration adapter is the transmission factor. Specifically, the transmission factor is the scattering parameter S. 21 The transmission factor relates to the forward transmission factor, or forward voltage gain, and represents the transmission without excitation at port 2. In effect, the transmission factor defines the ratio of the output power waveform at port 2 to the input power waveform at port 1.

[0042] In other words, the coupling capacitance of a universal artificial antenna and calibration adapter is based on the transmission factor, i.e., the scattering parameter S. 21 It is measured by a network analyzer.

[0043] In one aspect of the invention, the capacitance of the universal artificial antenna is based on the ratio of the scattering parameter associated with the universal artificial antenna coupled to the calibration adapter to the frequency of the measurement signal used, such as the scattering parameter measured in a first measurement setting. The scattering parameter itself depends on the frequency of the measurement signal used, and therefore, the capacitance of the universal artificial antenna can also depend on the frequency of the measurement signal used. In other words, the capacitance of the universal artificial antenna is based on the scattering parameter associated with the universal artificial antenna coupled to the calibration adapter divided by 2π·f.

[0044] Therefore, the formula for calculating the coupling capacitance of the universal artificial antenna coupled to the calibration adapter can be expressed by the following equation, where both the universal artificial antenna and the calibration adapter are connected to the network analyzer:

[0045]

[0046] Where C k It is the capacitor of a general-purpose artificial antenna, S 21,1 is the scattering parameter of the universal artificial antenna coupled to the calibration adapter, which is determined in the first measurement setting, f is the frequency of the measurement signal used, and c is a proportionality constant.

[0047] A general-purpose artificial antenna may include two 25Ω resistors and a capacitor, and / or wherein the calibration adapter includes two 25Ω resistors.

[0048] Generally, it is preferable to use a universal artificial antenna and a calibration adapter with the same number of resistors (especially resistors with the same resistance). This provides a uniform distribution of resistors and an overall symmetrical measurement setup for determining the coupling capacitance of the universal artificial antenna in a simplified manner.

[0049] Furthermore, artificial antennas and calibration adapters with 25Ω resistors are commonly used to calibrate monopole antennas, for example, via ECSMs known in the art. These artificial antennas and calibration adapters can also be used in the method according to the invention, thereby reducing the effort required because it is not necessary to use a specific antenna or specific calibration adapter for the method according to the invention.

[0050] In a further aspect of the invention, the amplification of the matched device can be calculated by using the ratio of scattering parameters associated with a general artificial antenna and scattering parameters associated with a calibration adapter.

[0051] Therefore, the amplification and input capacitance of the matching device can be easily determined based on the scattering parameters.

[0052] In particular, the input capacitance and amplification of the matching device are proportional to the coupling capacitance of a general artificial antenna.

[0053] In other words, the high coupling capacitance of a general-purpose artificial antenna results in high input capacitance and amplification of the matching device, while the small coupling capacitance of a general-purpose artificial antenna results in small input capacitance of the matching device.

[0054] According to another aspect of the invention, the input capacitance of the matching device is calculated based on the capacitance of the universal artificial antenna and the ratio of the scattering parameters associated with the universal artificial antenna (in the second measurement setting) and the scattering parameters associated with the calibration adapter (in the third measurement setting).

[0055] Specifically, the capacitance of the matching device can be calculated based on the following formula:

[0056]

[0057] Where C e To match the capacitance of the device, S 21,3 To calibrate the adapter's scattering parameters, which are determined in the third measurement setting, S 21,2 The scattering parameters of the general-purpose artificial antenna are determined in the second measurement setting, and C k This is the coupling capacitor for a general-purpose artificial antenna.

[0058] In other words, the input capacitance of the matching device can be calculated from, for example, measurements of two scattering parameters in two different measurement settings. As mentioned above, the scattering parameters are measured using a network analyzer, and the coupling capacitance of the general-purpose artificial antenna used is the previously calculated coupling capacitance.

[0059] In general, this formula describes the effect of the matching device on the scattering parameters of the calibration adapter or general artificial antenna in a measurement setup where the calibration adapter or general artificial antenna is connected to the matching device and network analyzer.

[0060] According to a further aspect of the invention, the matching device includes at least a capacitor, an amplifier, and an impedance. The capacitor is associated with the input of the matching device, thereby defining the (input) capacitance of the matching device.

[0061] The capacitance of a capacitor can be calculated using the formula described above. The amplification of an amplifier can also be calculated.

[0062] The scattering parameter S, associated with a general artificial antenna and used in the formula above, 21,3 This is the transmission factor. The transmission factor is measured using a network analyzer coupled to a universal artificial antenna and a matching device, for example, in a third measurement setup. Therefore, in the corresponding measurement setup, the network analyzer is connected to the universal artificial antenna, which is connected to the matching device, and the matching device is coupled to the network analyzer.

[0063] Scattering parameter S associated with the calibration adapter 21,2 This is also the transmission factor. This transmission factor is also measured using a network analyzer coupled to the calibration adapter and the matching device, for example, in the second measurement setting. The second measurement setting is similar to the third measurement setting described above, for which the network analyzer is connected to the calibration adapter instead of a generic artificial antenna.

[0064] In another aspect of the invention, the capacitance of the monopole antenna is determined based on the capacitance of the matching device, the scattering parameters associated with the general artificial antenna measured when the monopole antenna is connected to the matching device and the general artificial antenna, and the scattering parameters associated with the calibration adapter measured when the monopole antenna is connected to the matching device and the calibration adapter.

[0065] In other words, the capacitance of a monopole antenna can be calculated based on previously determined capacitances, such as the coupling capacitance of a general artificial antenna and the input capacitance of the matching device, as well as scattering parameters determined in different measurement settings, namely the scattering parameters associated with the general artificial antenna in the fourth measurement setting and the scattering parameters associated with the calibration adapter in the fifth measurement setting.

[0066] The capacitance of a monopole antenna can be calculated using the following formula:

[0067]

[0068] Where C a It is the capacitance of a monopole antenna, S 21,5 It is a scattering parameter associated with the calibration adapter, which is measured in the fifth measurement setting, S 21,4 It is a scattering parameter associated with a general-purpose artificial antenna, which is measured in the fourth measurement setting, C k It is the coupling capacitor of a general-purpose artificial antenna, and C e It is the input capacitor of the matching device.

[0069] Similarly, the coupling capacitance of a general-purpose artificial antenna and the input capacitance of the matching device can be determined based on the scattering parameters determined in different measurement settings, i.e., by using the formula above.

[0070] Therefore, it is noted that all capacitances calculated within the method according to the invention are based solely on measured scattering parameters, thus eliminating the need for further properties of individual components (i.e., monopole antennas, matching devices, calibration adapters, or general artificial antennas) to determine the antenna factor.

[0071] A monopole antenna can be connected in parallel with a general-purpose artificial antenna.

[0072] The term "parallel connection" is understood to mean that the input and output ports of a monopole antenna can be directly connected to the input and output ports of a general-purpose artificial antenna via electrical connectors. Alternatively, the corresponding inputs and corresponding outputs are connected to associated nodes respectively. Therefore, a voltage is generated between the general-purpose artificial antenna and the monopole antenna.

[0073] In another aspect of the invention, the antenna factor of a monopole antenna is corrected by using a correction factor, wherein the correction factor is calculated by two different ratios, both of which depend on the matching device, the general artificial wire, and the capacitance of the monopole antenna.

[0074] It is necessary to correct the antenna factor of a monopole antenna because the capacitance of a general artificial antenna is not equal to the self-capacitance of a monopole antenna, as is the case with ECSM, for example.

[0075] In other words, the use of correction factors allows for the use of general artificial antennas, making them independent of specific artificial antennas matched with monopole antennas.

[0076] It should also be noted that the correction factor is calculated based solely on the previously calculated capacitances of the monopole antenna, general-purpose artificial antenna, and matching device. Therefore, it is not necessary to know any of these values ​​beforehand.

[0077] Another advantage is that the correction factor is also indirectly based solely on the scattering parameters of various measurements that can be accurately measured. This makes the entire method and the calibration of the monopole antenna less sensitive to measurement uncertainties.

[0078] In embodiments of the present invention, the correction factor is the product of the following: the ratio of the capacitance of the general artificial antenna to the sum of the capacitances of the general artificial antenna and the adjustment unit, and the ratio of the sum of the capacitances of the monopole antenna and the adjustment unit to the capacitance of the monopole antenna.

[0079] This leads to the following formula for the correction factor:

[0080]

[0081] Among them, K c C is a correction factor used to correct the mismatch between the capacitance of a general-purpose artificial antenna and that of a monopole antenna. k For the coupling capacitance of a general-purpose artificial antenna, C e To match the input capacitance of the device and C a The capacitance is for a monopole antenna.

[0082] According to a further aspect of the invention, the capacitance value of the monopole antenna used to calculate the correction factor is based on the capacitance determined by the matching device, the general artificial antenna, and the monopole antenna, or calculated according to a geometric model.

[0083] However, the correction factor can only be calculated using a geometric model specific to the monopole antenna. Specifically, the monopole antenna must be a cylindrical monopole antenna.

[0084] The antenna factor of a monopole antenna can also depend on the height of the monopole antenna above ground potential.

[0085] In the following text, "the height of the monopole antenna" refers to the effective height of the monopole antenna relative to the ground.

[0086] Due to the asymmetric nature of monopole antennas, they are fundamentally incapable of suppressing common-mode currents. In contrast, symmetrical antennas with a qualified balun can suppress unwanted common-mode effects. Therefore, monopole antennas are typically mounted on the ground or at least have low inductance and a short ground connection to the absorber-lined shielded enclosure. If a monopole antenna must be mounted off the ground, height correction must be applied to improve measurement uncertainty.

[0087] In addition, the antenna factor also depends on the scattering parameters associated with the general artificial antenna coupled in parallel with the monopole antenna, i.e., in the fourth measurement setting.

[0088] This leads to the following final formula used to calculate the antenna factor:

[0089]

[0090] Among them, F ac It is the antenna factor, S 21,4 These are the scattering parameters of a general-purpose artificial antenna coupled to a monopole antenna, measured in the fourth measurement setting, h. e It is the effective height of the monopole antenna and K c It is the correction factor as described above.

[0091] According to another aspect of the invention, the monopole antenna is fixed to a tripod or ground plane during measurement. This is necessary to determine the effective height of the monopole antenna and to accurately calculate the antenna factor. However, for calculating the antenna factor, it makes no difference whether the monopole antenna is fixed to a tripod or ground plane during measurement. For example, the monopole antenna can be mounted on a tripod at a height of 1 m. Attached Figure Description

[0092] The foregoing aspects and many of the advantages that are derived from the claimed subject matter will become more readily understood, as they become better understood when taken in conjunction with the accompanying drawings, by referring to the following detailed description, in which:

[0093] Figure 1 schematically illustrates an ECSM measurement apparatus for determining the antenna factor of a monopole antenna according to the prior art;

[0094] Figure 2 An outline of the components of a measuring device according to an embodiment of the present invention is shown schematically;

[0095] Figure 3 schematically shown Figure 2 The first measurement setting of the measuring device is used to determine the capacitance of a general-purpose artificial antenna;

[0096] Figure 4 It schematically shows the following based on Figure 3 The coupling of the first measurement setup's universal artificial antenna to the calibration adapter;

[0097] Figure 5 schematically shown Figure 2 The second measurement setting of the measuring device is used to determine the capacitance of the matching device;

[0098] Figure 6 schematically shown Figure 2 The third measurement setting of the measuring device is used to determine the capacitance of the matching device.

[0099] Figure 7It is schematically shown in the form of a circuit diagram. Figure 5 The second measurement setting,

[0100] Figure 8 It is schematically shown in the form of a circuit diagram. Figure 7 The third measurement setting;

[0101] Figure 9 schematically shown Figure 2 The fourth measurement setting of the measuring device is used to determine the capacitance of the matching device;

[0102] Figure 10 schematically shown Figure 2 The fifth measuring setting of the measuring device is used to determine the capacitance of the matching device according to the invention; and

[0103] Figure 11 A method for determining the antenna factor of a monopole antenna according to the present invention is illustrated schematically, the method being carried out by means of... Figure 2 This is accomplished using a measuring device. Detailed Implementation

[0104] The detailed description set forth below with reference to the accompanying drawings is intended as a description of various embodiments of the disclosed subject matter and not as an indication of only one embodiment, wherein similar numerals refer to similar elements. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or superior to other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed.

[0105] For the purposes of this invention, the phrase "at least one of A, B, and C" refers, for example, to (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when more than three elements are listed. In other words, the term "at least one of A and B" generally means "A and / or B," i.e., "A" alone, "B" alone, or "A and B."

[0106] Figure 1 schematically illustrates a measurement device 1 known in the prior art, which is used to determine the antenna factor using the equivalent capacitor substitution method (ECSM).

[0107] The measuring device 1 includes a signal source 2 that provides a signal (e.g., voltage), an artificial antenna 4 that replaces a monopole antenna, a matching device 6 with an amplifier, and a receiver 8 that receives the signal (i.e., voltage).

[0108] In the measuring device 1, the monopole antenna is replaced by an artificial antenna 4, which must correspond to the monopole antenna. Therefore, the measurement is not performed using the monopole antenna itself, but using the specific artificial antenna 4.

[0109] Artificial antenna 4 includes two resistors, R1 and R2, each with a resistance of 25Ω, which are needed to combine the length of the common monopole antenna with a length of 1m. The ratio of resistors R1 and R2 is typically 1:1, such that the driving voltage V from signal source 2... D Divide by 2, which corresponds to the height correction factor for a 1m long monopole antenna.

[0110] Additionally, the artificial antenna 4 includes a capacitor C representing the self-capacitance of a monopole antenna. a The self-capacitance of a monopole antenna depends, among other things, on the length and / or diameter of the monopole antenna.

[0111] Together with matching device 6, they form a capacitive voltage divider. Following the capacitive voltage divider is an amplifier, which is also included in matching device 6. The amplifier must convert V... L It is delivered to a 50Ω load. The amplifier's gain can be scaled such that, according to formula F... A =V D -V L To obtain an appropriate antenna factor (F) A ).

[0112] Therefore, in order to calibrate a monopole antenna according to the ECSM method, the artificial antenna 4 must be matched with the monopole antenna to be calibrated. Thus, a specific artificial antenna 4 is required for each monopole antenna.

[0113] Furthermore, since height correction depends on the two resistors R1 and R2 of the artificial antenna 4, height correction is only possible in a limited way.

[0114] In addition, there are many uncertainties that may negatively affect the determination of the antenna factor.

[0115] exist Figures 2 to 10 The measuring device 10 according to an embodiment of the present invention is shown in different configurations, which are necessary for determining the antenna factor of a monopole antenna.

[0116] Measuring device 10 includes Figure 2 The different components are shown in isolation, with different measurement settings based on what will be explained in more detail below. Figure 2 The measuring device 10 shown is constructed from the components of the measuring device 10 shown.

[0117] In the first measurement setting 12 of the measuring device 10, such as Figure 3 As shown, the universal artificial antenna 14 is coupled to the calibration adapter 16. The first measurement setting 12 is used to determine the coupling capacitance of the universal artificial antenna 14.

[0118] The universal artificial antenna 14 and calibration adapter 16 are also connected to the network analyzer 18 via line 20. Specifically, one line 20 connects the universal artificial antenna 14 to a first port of the network analyzer 18, and a second line 20 connects the calibration adapter 16 to a second port of the network analyzer 18. Line 20 can be implemented using electrical conductors, such as connecting cables, particularly coaxial cables.

[0119] Network analyzer 18 provides a measurement signal via a first port or a second port, which is received by the corresponding other port of network analyzer 18. Network analyzer 18 is then able to analyze the received signal.

[0120] Network analyzer 18 is configured to determine the scattering parameters, S-parameters, of the universal artificial antenna 14 coupled to calibration adapter 16. Typically, the scattering parameters depend on the frequency of the measurement signal used.

[0121] Specifically, the scattering parameters of the universal artificial antenna 14 and calibration adapter 16 determined by the network analyzer 18 are the transmission factor, preferably the scattering parameter S. 21 .

[0122] Figure 4 Schematic detail shown Figure 3 The coupling of the universal artificial antenna 14 and the calibration adapter 16 shown illustrates the internal components of the universal artificial antenna 14 and the calibration adapter 16.

[0123] The general-purpose artificial antenna 14 includes two resistors 22 (e.g., with a resistance of 25Ω) and a capacitor 24.

[0124] Two resistors are connected in a row.

[0125] The capacitor 24 of the general-purpose artificial antenna 14 is connected to a connector between two resistors 22, for example via a center tap.

[0126] Capacitor 24 may have a capacitance of 15pF. One side of capacitor 24 is connected to a center tap located between the two resistors 22, while the other side of capacitor 24 is coupled to calibration adapter 16.

[0127] The calibration adapter 16 includes two resistors 26, for example, with a resistance of 25Ω, which are also connected in a row. The calibration adapter 16 has an interface through which it is connected to the universal artificial antenna 14, wherein the interface is associated with a center tap located between the two resistors 26.

[0128] The overall arrangement of the two resistors 22 of the general-purpose artificial antenna 14 and the two resistors 26 of the calibration adapter 16 is symmetrical about the capacitor 24 of the general-purpose artificial antenna 14.

[0129] Figure 5 A second measurement setup 28 is schematically shown, which includes a universal artificial antenna 14 and a network analyzer 18. However, in the second measurement setup 28, the universal artificial antenna 14 is connected to a matching device 30 instead of a calibration adapter 16. In other words, the calibration adapter 16 used in the first measurement setup 12 is replaced by the matching device 30.

[0130] In the second measurement setup 28, the first port of the network analyzer 18 is connected to the universal artificial antenna 14, while the second port of the network analyzer 18 is connected to the matching device 30.

[0131] Using this second measurement setup 28, the effect of the matching device 30 on the scattering factor of the general-purpose artificial antenna 14 can be determined.

[0132] In other words, the scattering parameters associated with the universal artificial antenna 14 are measured in the second measurement setting 28. Based on the scattering parameters associated with the universal artificial antenna 14, the capacitance of the matching device 30 can be determined, as will be discussed in more detail later.

[0133] The scattering parameter associated with the general artificial antenna 14, measured in the second measurement setting 28, is again the transmission factor, i.e., the S-parameter S. 21 .

[0134] like Figure 6 As shown, the third measurement setup 32 is similar to the second measurement setup 28. The only difference between the two setups 28 and 32 is that in the third measurement setup 32, the matching device 30 is coupled to the calibration adapter 16 instead of the universal artificial antenna 14. In other words, in the third measurement setup 32, the calibration adapter 16 has replaced the universal artificial antenna 14, relative to the second measurement setup 28.

[0135] Using the third measurement setting 32, the effect of the matching device 30 on the scattering factor of the calibration adapter 16 can be determined.

[0136] In other words, the scattering parameters associated with the calibration adapter 16 are measured in the third measurement setting 32. Based on the scattering parameters associated with the calibration adapter 16, the capacitance of the matching device 30 can be determined, as will be discussed in more detail later.

[0137] The scattering parameter associated with the calibration adapter 16, measured in the third measurement setting 32, is again the transmission factor, i.e., the S-parameter S. 21 .

[0138] exist Figure 7In the circuit diagram, a second measurement setting 28, in which the universal artificial antenna 14 is coupled to the matching device 30, is shown, while a third measurement setting 32, in which the calibration adapter 16 is coupled to the matching device 30, is shown. Figure 8 The circuit diagram is shown in the figure.

[0139] like Figure 7 and Figure 8 As shown, the matching device 30 includes a capacitor 34, such as an input capacitor, whose capacitance is determined by the second measurement setting 28 and the third measurement setting 32.

[0140] Additionally, the matching device 30 includes an amplifier 36 and an adjustable impedance 38. The amplification of the amplifier 36 can also be determined by the second measurement setting 28 and the third measurement setting 32.

[0141] The scattering parameters determined in the second measurement setting 28 and the third measurement setting 32 are used to calculate the input capacitance of the matching device 30, i.e., the capacitance of capacitor 34, as will be referred to later. Figure 11 As described at the time.

[0142] Figure 9 The fourth measurement setting 40 of the measuring device 10 is schematically shown, which is used to measure the scattering factor, based on which the capacitance of the monopole antenna 42 can be determined.

[0143] The fourth measurement setting 40 is similar to Figure 5 The second measurement setup 28 is shown. In addition to the components of the second measurement setup 28, the fourth measurement setup 40 additionally includes a monopole antenna 42.

[0144] The monopole antenna 42 is connected in parallel to the general-purpose artificial antenna 14. The monopole antenna 42 and the general-purpose artificial antenna 14 are interconnected via line 20.

[0145] By connecting the monopole antenna 42 in parallel to the general artificial antenna 14, the antenna factor can be calculated correctly in a simplified manner, making it easier to calibrate the monopole antenna 42.

[0146] The monopole antenna 42 can be mounted either on a tripod and ground plane (not shown), or directly on a ground plane placed on the ground. The tripod can be 1m high.

[0147] In the fourth measurement setting 40, the network analyzer 18 measures the scattering parameters associated with the general artificial antenna 14 in the corresponding measurement setting 40.

[0148] Based on the measured scattering parameters, the next important factor is the transport factor, i.e., the S-parameter S. 21 From this, we can draw conclusions about the capacitance of the monopole antenna 42.

[0149] To calculate the capacitance of the monopole antenna 42, it is necessary to... Figure 10 Further measurements are performed in the fifth measurement setting 44 shown.

[0150] The fifth measurement setting 44 is similar to the fourth measurement setting 40, but in the fifth measurement setting 44, the universal artificial antenna 14 has been replaced by the calibration adapter 16.

[0151] Therefore, in the fifth measurement setting 44, the calibration adapter 16 is connected in parallel to the monopole antenna 42 instead of the general artificial antenna 14, as is the case in the fourth measurement setting 40.

[0152] The fifth measurement setting 44 is used to determine the scattering parameters associated with the calibration adapter 16, which is the transmission factor of the calibration adapter 16, i.e., the S-parameter S. 21 .

[0153] Based on the ratio of the scattering parameters associated with the calibration adapter 16 obtained by the fifth measurement setting 44 to the scattering parameters associated with the general artificial antenna 14 obtained by the fourth measurement setting 40, along with the coupling capacitance of the general artificial antenna 14 and the input capacitance of the calibration adapter 16, the capacitance of the monopole antenna 42 can be calculated. Different calculated capacitances are then used to calculate the antenna factor of the monopole antenna 42. In the following, with reference to... Figure 11 This becomes clear when the method for determining the antenna factor of the monopole antenna 42 is shown. Based on this, the monopole antenna 42 can be calibrated.

[0154] In the first step S1, a general-purpose artificial antenna 14 is provided and its coupling capacitance is determined. Therefore, using... Figure 3 The first measurement setup 12 is shown, in which a universal artificial antenna 14 is coupled to a calibration adapter 16. Furthermore, a network analyzer 18 is connected to both the universal artificial antenna 14 and the calibration adapter 16. The scattering parameters associated with the universal artificial antenna 14 coupled to the calibration adapter 16 are determined by the network analyzer 18; that is, the scattering parameters associated with the universal artificial antenna 14 in the first measurement setup 12.

[0155] The coupling capacitance of the general-purpose artificial antenna 14 is based on the ratio of the scattering parameters associated with the general-purpose artificial antenna 14 coupled to the calibration adapter 16 to the frequency of the measurement signal used.

[0156] Therefore, the formula for calculating the coupling capacitance of the general-purpose artificial antenna 14 is as follows:

[0157]

[0158] Where C k It is the coupling capacitor of the general-purpose artificial antenna 14, and S 21,1These are the scattering parameters associated with the universal artificial antenna 14 coupled to the calibration adapter 16, i.e., the scattering parameters obtained in the first measurement setting 12. Furthermore, a scaling constant c is used.

[0159] In the second step S2, a matching device 30 for the measuring device 10 is provided. The matching device 30 is connected to the universal artificial antenna 14, thereby replacing the calibration adapter 16. Therefore, [the following is obtained] Figure 5 The second measurement setup 28 is shown. In the second measurement setup 28, the scattering parameters associated with the general-purpose artificial antenna 14 are measured by the network analyzer 18.

[0160] In the third step S3, a calibration adapter 16 for the measuring device 10 is provided, and the matching device 30 is connected to the calibration adapter 16, which replaces the universal artificial antenna 14, thereby obtaining... Figure 6 The third measurement setting is shown. In the third measurement setting 32, the scattering parameters associated with the calibration adapter 16 are determined by the network analyzer 18.

[0161] Based on the information already collected, the input capacitance and amplification of the matching device 30 can be determined, and in particular, calculated, in the fourth step S4.

[0162] In practice, the input capacitance of the matching device 30 can be determined based on the coupling capacitance of the universal artificial antenna 14, based on the ratio of the scattering parameters associated with the universal artificial antenna 14 obtained in the first measurement setting 12 and the scattering parameters associated with the calibration adapter 16 obtained in the second measurement setting 28.

[0163] Specifically, the input capacitance of the matching device 30 can be calculated using the following formula:

[0164]

[0165] Where C e It is the input capacitor of matching device 30, S 21,3 The scattering parameters of the calibration adapter 16 obtained in the third measurement setting 32, S 21,2 The scattering parameters of the general artificial antenna 14 obtained in the second measurement setting 28, and C k This is the coupling capacitance of the general-purpose artificial antenna 14. Therefore, the input capacitance of the matching device 30 is proportional to the coupling capacitance of the general-purpose artificial antenna 14.

[0166] In the fifth step S5, a monopole antenna 42 of the measurement setup 10 is provided and connected to the matching device 30 and the universal artificial antenna 14, thereby providing... Figure 9The fourth measurement setup 40 is shown. Then, in the fourth measurement setup 40, the scattering parameters associated with the general artificial antenna 14 are measured by the network analyzer 18.

[0167] In step S6, a monopole antenna 42 is provided and connected to the matching device 30 and calibration adapter 16. In other words, the universal artificial antenna 14 is replaced by the calibration adapter 16, thereby obtaining... Figure 10 The fifth measurement setting 44 is shown in the figure.

[0168] In the sixth step, the scattering parameters associated with the calibration adapter 16 are measured by the network analyzer 18 in the fifth measurement setting 44.

[0169] In the seventh step S7, the capacitance of the monopole antenna 42 can be calculated based on the coupling capacitance of the general artificial antenna 14 calculated in the first step, the input capacitance of the matching device 30 calculated in the fourth step, and the ratio of the scattering parameters associated with the general artificial antenna 14 measured in the fifth step and the scattering parameters associated with the calibration adapter 16 measured in the sixth step.

[0170] The corresponding formula for calculating the capacitance of the monopole antenna 42 is as follows:

[0171]

[0172] Where C a It is the capacitor of the monopole antenna 42, S 21,5 The scattering parameters associated with calibration adapter 16 are obtained in the fifth measurement setting 44, S 21,4 The scattering parameters associated with the general-purpose artificial antenna 14 are obtained in the fourth measurement setting 40, C. k It is the coupling capacitor of the general-purpose artificial antenna 14, and C e It is the input capacitor of the matching device 30.

[0173] As an alternative to determining the capacitance of monopole antenna 42 using steps five and six as outlined above, the capacitance of monopole antenna 42 can be determined using a geometric model. However, this is generally only applicable to a specific type of monopole antenna, namely a cylindrical monopole antenna.

[0174] In the eighth step, the antenna factor of the monopole antenna 42 is determined based on the capacitance of the monopole antenna 42, the coupling capacitance of the general artificial antenna 14, and the input capacitance of the matching device 30.

[0175] The formula for calculating the antenna factor of monopole antenna 42 takes into account the correction factor, since the capacitance of general artificial antenna 14 is not equal to the self-capacitance of monopole antenna 42.

[0176] This correction factor is called K.c And it can be calculated as follows:

[0177]

[0178] Among them, C k For the coupling capacitance of a general-purpose artificial antenna, C e To match the input capacitance of the device, and C a The capacitance is for a monopole antenna.

[0179] Therefore, the correction factor is the product of two different ratios of the capacitance of the matching device 30, the universal artificial antenna 14, and the calibration adapter 16.

[0180] The capacitance of the monopole antenna 42 used to calculate the correction factor can be based on the capacitance determined by the monopole antenna 42, the general artificial antenna 14, and the calibration adapter 16, or it can be calculated based on the geometric model shown above.

[0181] Since the antenna factor also depends on the height of the monopole antenna 42 above the ground potential, the monopole antenna 42 can be fixed to a tripod or ground plane 46 during the measurement. In particular, the effective height of the monopole antenna must also be included in the formula during the measurement in the fifth and sixth steps.

[0182] Therefore, the final formula for calculating the antenna factor of the monopole antenna 42 is as follows:

[0183]

[0184] Among them, F ac For antenna factor, S 21,4 For the scattering parameters of the general-purpose artificial antenna 14 coupled to the monopole antenna 42, measured in the fourth measurement setting 40, h e The effective height of the monopole antenna, and K c For correction factors.

[0185] The method according to the invention enables reliable determination of antenna factors and calibration of monopole antennas based on the measurement of scattering parameters using a network analyzer.

[0186] Some embodiments of this disclosure, particularly corresponding modules and / or units and / or devices, utilize circuit systems (e.g., one or more circuits) to implement the standards, protocols, methods, or techniques of this disclosure, operatively coupling two or more components, generating information, processing information, analyzing information, generating signals, encoding / decoding signals, converting signals, transmitting and / or receiving signals, controlling other devices, etc. Any type of circuit system can be used.

[0187] In embodiments, among others, the circuit system includes one or more computing devices, such as a processor (e.g., a microprocessor), a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a system-on-a-chip (SoC), or the like, or any combination thereof, and may include discrete digital or analog circuit elements or electronic devices, or combinations thereof. In embodiments, the circuit system includes hardware circuit implementations (e.g., implementations in analog circuit systems, implementations in digital circuit systems, and the like, and combinations thereof).

[0188] In embodiments, the circuit system includes a combination of circuitry and a computer program product having software or firmware instructions stored on one or more computer-readable storage media that cooperate to cause the device to perform one or more protocols, methods, or techniques described herein. In embodiments, the circuit system includes circuitry that requires software, firmware, and the like for operation, such as, for example, a microprocessor or portions thereof. In embodiments, the circuit system includes one or more processors or portions thereof, along with accompanying software, firmware, hardware, and the like.

[0189] This application may refer to quantities and numbers. Unless otherwise stated, such quantities and numbers should not be considered limiting, but rather exemplary possible quantities or numbers associated with this application. Also in this respect, this application may use the term "multiple" to refer to quantities or numbers. In this respect, the term "multiple" means any number that is more than one, such as two, three, four, five, etc. The terms "about," "approximately," "close to," etc., mean plus or minus 5% of the stated value.

Claims

1. A method for determining an antenna factor of a monopole antenna (42), the method comprising the steps of: - providing a generic artificial antenna (14) and determining a coupling capacitance of the generic artificial antenna (14); - providing a matching device (30), connecting the matching device (30) with the generic artificial antenna (14), and measuring a scattering parameter associated with the generic artificial antenna (14); - providing a calibration adapter (16), connecting the matching device (30) with the calibration adapter (16) such that the calibration adapter (16) replaces the generic artificial antenna (14), and measuring a scattering parameter associated with the calibration adapter (16); - determining an input capacitance of the matching device (30) using a ratio of the scattering parameter associated with the generic artificial antenna (14) and the scattering parameter associated with the calibration adapter (16); - providing a monopole antenna (42), connecting the monopole antenna (42) with the matching device (30) and the generic artificial antenna (14), and measuring a scattering parameter associated with the generic artificial antenna (14); - providing the calibration adapter (16), connecting the monopole antenna (42) with the matching device (30) and the calibration adapter (16) such that the calibration adapter (16) replaces the generic artificial antenna (14), and measuring a scattering parameter associated with the calibration adapter (16); - determining a capacitance of the monopole antenna (42) based on the coupling capacitance of the generic artificial antenna (14), the input capacitance of the matching device (30), and the ratio of the scattering parameter associated with the generic artificial antenna (14) and the scattering parameter associated with the calibration adapter (16); and - determining an antenna factor of the monopole antenna (42) based on the capacitance of the monopole antenna (42), the coupling capacitance of the generic artificial antenna (14), and the input capacitance of the matching device (30). The coupling capacitance of the generic artificial antenna (14) is determined by coupling the generic artificial antenna (14) to the calibration adapter (16) and measuring a scattering parameter associated with the generic artificial antenna (14) coupled to the calibration adapter (16).

2. The method of claim 1, wherein, The scattering parameter associated with the generic artificial antenna (14) coupled to the calibration adapter (16) is a transmission factor.

3. The method according to one of claims 1 or 2, wherein, The capacitance of the generic artificial antenna (14) is based on a ratio of the scattering parameter associated with the generic artificial antenna (14) coupled to the calibration adapter (16) and a frequency of a measurement signal used.

4. The method according to one of the preceding claims, wherein, The generic artificial antenna (14) comprises two 25 Ω resistors and one capacitor, and / or wherein the calibration adapter (16) comprises two 25 Ω resistors.

5. The method according to one of the preceding claims, wherein, The amplification of the matching device (30) is also determined by using a ratio of the scattering parameter associated with the generic artificial antenna (14) and the scattering parameter associated with the calibration adapter (16).

6. The method according to one of the preceding claims, wherein, ​ 7. The method of claim 6, wherein, The input capacitance and amplification of the matching device (30) is proportional to the capacitance of the universal artificial antenna (14).

8. The method according to one of the preceding claims, wherein, The input capacitance of the matching device (30) is determined based on the capacitance of the universal artificial antenna (14) and a ratio of a scattering parameter associated with the universal artificial antenna (14) and a scattering parameter associated with the calibration adapter (16).

9. The method according to one of the preceding claims, wherein, The matching device (30) comprises at least a capacitor, an amplifier and an impedance.

10. The method according to one of the preceding claims, wherein, The scattering parameter associated with the universal artificial antenna is a transmission factor.

11. The method of claim 1, wherein, The scattering parameter associated with the calibration adapter (16) is a transmission factor.

12. The method according to one of the preceding claims, wherein, The capacitance of the monopole antenna (42) is determined based on the capacitance of the matching device (30), the capacitance of the matching device (30), a scattering parameter associated with the universal artificial antenna (14) measured when the monopole antenna (42) is connected to the matching device (30) and the universal artificial antenna (14), and a scattering parameter associated with the calibration adapter (16) measured when the monopole antenna (42) is connected to the matching device (30) and the calibration adapter (16).

13. The method according to one of the preceding claims, wherein, The monopole antenna (42) is connected in parallel to the universal artificial antenna (14).

14. The method according to one of the preceding claims, wherein, The antenna factor of the monopole antenna (42) is corrected by using a correction factor, wherein the correction factor is determined by two different ratios, wherein the ratios both depend on the capacitances of the matching device (30), the universal artificial antenna (14) and the monopole antenna (42).

15. The method of claim 14, wherein, The correction factor is a product of a ratio of the capacitance of the universal artificial antenna (14) to the sum of the capacitances of the universal artificial antenna (14) and an adjustment unit, and a ratio of the sum of the capacitances of the monopole antenna (42) and the adjustment unit to the capacitance of the monopole antenna (42).

16. The method according to one of claims 14 or 15, wherein, The capacitance value of the monopole antenna (42) used for determining the correction factor is determined based on the determined capacitances of the matching device (30), the universal artificial antenna (14) and the monopole antenna (42), or according to a geometrical model.

17. The method according to one of the preceding claims, wherein, The antenna factor of the monopole antenna (42) further depends on a height of the monopole antenna (42) above ground potential.

18. The method according to one of the preceding claims, wherein, The monopole antenna (42) is fixed to a tripod or a ground plate during the measurement.

19. A method for determining an antenna factor of a monopole antenna, the method comprising the steps of: - providing a universal artificial antenna and determining a coupling capacitance of the universal artificial antenna; - providing a matching device, connecting the matching device with the universal artificial antenna and measuring a scattering parameter associated with the universal artificial antenna; - providing a calibration adapter, connecting the matching device with the calibration adapter such that the calibration adapter replaces the universal artificial antenna and measuring a scattering parameter associated with the calibration adapter; - determining an input capacitance of the matching device using a ratio of the scattering parameter associated with the universal artificial antenna and the scattering parameter associated with the calibration adapter; - determining an antenna factor of the monopole antenna using the input capacitance of the matching device and the scattering parameter associated with the universal artificial antenna; and - determining a height of the monopole antenna above ground potential. - providing a monopole antenna, connecting the monopole antenna with the matching device and the generic artificial antenna, and measuring scattering parameters associated with the generic artificial antenna; - providing the calibration adapter, connecting the monopole antenna with the matching device and the calibration adapter, such that the calibration adapter replaces the generic artificial antenna, and measuring scattering parameters associated with the calibration adapter; - determining a capacitance of the monopole antenna based on a geometrical model of the monopole antenna; and - determining an antenna factor of the monopole antenna based on the capacitance of the monopole antenna, a coupling capacitance of the generic artificial antenna, and an input capacitance of the matching device.

20. A measuring device (10) for determining the antenna factor of a monopole antenna, wherein The measuring device (10) has different measurement setups, wherein the measuring device (10) comprises a generic artificial antenna (14), a calibration adapter (16), a matching device (30), a monopole antenna (42), and a network analyzer (18), wherein, in a first measurement setup (12) for determining a capacitance of the generic artificial antenna (14), the generic artificial antenna (14) is coupled to the calibration adapter (16); wherein, in a second measurement setup for measuring scattering parameters associated with the generic artificial antenna (14), the matching device (30) is coupled to the generic artificial antenna (14), and the matching device (30) and the artificial antenna (14) are coupled to the network analyzer (18); wherein, in a third measurement setup for measuring scattering parameters associated with the calibration adapter (16), the matching device (30) is coupled to the calibration adapter (16), and the matching device (30) and the calibration adapter (16) are coupled to the network analyzer (18); wherein, in a fourth measurement setup for measuring scattering parameters associated with the generic artificial antenna (14), the matching device (30) is coupled to the monopole antenna (42), the generic artificial antenna (14) is coupled to the monopole antenna (42), and the generic artificial antenna (14) and the matching device (30) are coupled to the network analyzer (18); and wherein, in a fifth measurement setup for measuring scattering parameters associated with the calibration adapter (16), the matching device (30) is coupled to the monopole antenna (42), the calibration adapter (16) is coupled to the monopole antenna (42), and the calibration adapter (16) and the matching device (30) are coupled to the network analyzer (18).

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