TW515896B - Method for measuring broadband antenna - Google Patents

Abstract

The invention relates to a method for measuring broadband antenna, using EMC chamber to measure antenna factor of broadband antenna where a standard electrical field intensity is generated in the chamber so as to test the broadband antenna and acquire a first antenna factor, furthermore, proceed a computer simulation with respect to the broadband antenna to obtain a second antenna factor and compare the first antenna factor with the second antenna factor to acquire a lower uncertainty.

Description

515896 A 7 ____ B7 V. Description of the invention () This case is a method for measuring a wideband antenna, especially a method for measuring the antenna factor of a wideband antenna in an anechoic chamber, and then using the data obtained by computer simulation to verify the reliability of the antenna factor degree. In everyday life, the use of wireless transmission has become very popular, such as wireless mobile phones, wireless modems, wireless network cards, and so on. Wireless transmission mainly uses radio frequency (RF) transmission technology to enable end-users or users to achieve the purpose of real-time communication. In the design of the mechanism for transmitting and receiving signals, the antenna (Antenna) is an important element. The design of the antenna is usually completed according to the wavelength of the radio signal (Wireless Signal) with a suitable geometric shape of different length, width and height ratio of metal wires or planes. Common frequency-finding antennas include biconical antennas and logarithmic periods. A dipole antenna (LPDA, Log periodic dipole array), a dual logarithmic antenna (Bi-10g Antenna), a spiral antenna (Spirai Antenna), and so on. Ministry of Economic Affairs ¾ Property Bureau Xiaogong Juan #; ^ e: -ri-printing The IF antenna must be able to be used for the detection of electromagnetic interference (c). The conventional detection system places a broadband antenna in an open space, and then uses antenna testing equipment to verify the value of its antenna factor at different frequencies. However, due to the increasing complexity of the existing space and environment, there are all kinds of interference from all over the place. It is quite difficult to conduct thorough tests in this regard. However, if the open space test method is used blindly, the detection results will obviously cause considerable errors due to environmental variables. The purpose of this case is to propose an improved method based on the shortcomings of the above-mentioned conventional technology. An anechoic chamber 'is used to block any interference sources, and at the same time, the method of computer simulation is used to make the antenna factor test of the 1-band antenna more reliable. In order to achieve the above purpose, this case proposes a method for measuring a wideband antenna, which includes the following steps: 515896 A7 B7 V. Description of the invention () Provide an anechoic chamber to generate a standard electric field strength. Since the anechoic chamber is a simulated free space, the An anechoic chamber can be used to measure or correct the antenna, where a first antenna factor can be known in the dark of the radio; a computer simulation of the frequency-finding antenna to find a second antenna factor; and Compare the first antenna factor and the second antenna factor to obtain an antenna factor with a lower uncertainty. The method for measuring a broadband antenna as described above, wherein the broadband antenna includes a double cone antenna (Biconical Antenna), a log periodic dipole antenna (LPDA, L0g periodic dipole array), and a dual logarithmic antenna (Bi-10g Antenna), Spiral Antenna. As described in the method for measuring a wideband antenna, the anechoic chamber is a closed space constructed with an absorbing material, and its design should produce a uniform electric field strength. The method for measuring a broadband antenna as described above, wherein the antenna testing equipment is a Spectrum Analyzer. As described in the method for measuring a wide-band antenna, the electrical method is an electromagnetic wave computer simulation method using a method of moments. As described in the method for measuring a wideband antenna, the moment method can be used to obtain a test field attenuation value and an antenna phase center point. Ministry of Economic Affairs, Smart Finance, 4th Bureau 3: The method for measuring broadband antennas printed by the Industrial Cooperative Bone Cooperatives, where the phase center of the antenna is obtained includes a minimum phase change center method and a maximum current distribution method And an interpolation method. The method of measuring a broadband antenna as described above, wherein the broadband antenna is a broadband antenna capable of electromagnetic interference (EMC) detection. 515896 Λ 7 _________B7 V. Description of the Invention () ~ ---- The following drawings and detailed descriptions can be used to gain a deeper understanding: Figure 1. System architecture for measuring a wideband antenna in a preferred embodiment of the case. Figure 2. The antenna receives the electric field E and the voltage vR in the preferred embodiment of this case. Figure 3: The geometric diagram of the antenna phase center calculation in the preferred embodiment of this case. Figure 4. The layout of the site attenuation method of the preferred embodiment of this case. FIG. 1 is a system architecture for measuring a wideband antenna according to a preferred embodiment of the present invention. The standard antenna and the antenna under test that generate a known electric field strength are placed in an anechoic chamber 11 to perform a test operation. An antenna factor, on the other hand, the same antenna can be simulated by a computer to obtain a second antenna factor. The two antenna factors are compared. If they are similar, it means that the measured result has a higher probability. Reliability. The Tianben case is mainly used to test the broadband antenna of EMC (Eiectromagnetic Compatiblity, Electromagnetic Compatibility) detection. This type of antenna system includes a double cone antenna (Al Antenna), log periodic dipole antenna (lpda, Log periodic dipole array). ), Dual logarithmic antenna Antenna), spiral antenna (Spiral

Antenn ^ And the radio wave is darkened by-absorbing material construction-to delete space. The antenna test is also prepared as a spectrum analyzer (such as Qiaolian Analyzer). The computer simulation method is a two-moment method electromagnetic computer simulation method, which can accurately estimate the antenna factor. ^ Y " T finds the percentage reduction of an antenna phase center point ', and the antenna phase center point includes the minimum phase change center method, the maximum current distribution method, and the interpolation method. The numerical computer simulation method using the moment method is detailed as follows: Calculate the antenna factor 1 · site attenuation using the moment method electromagnetic simulation method (please read the precautions on the back first and then the page j-installation · the employee ’s intellectual property bureau employee consumption Printed by the cooperative (1) 515896 A7 V. Description of the invention (the definition of site attenuation A is A = kn · or AWBkV / dBuV) -VR (dBuV) Voltage of V-produced signal generator • ⑵ Intellectual Property Bureau of the Ministry of Economic Affairs f The voltages captured by the vR two-field intensity meter or spectrum analyzer printed by Fanghe are obtained from equation (1) and ⑵ are the readings of the signal generator and the readings of the spectrum analyzer, because It is called ⑹. The open circuit voltage v of the signal generator is 2 times the matching output voltage VD. Therefore, the equation (1) can be rewritten as follows: k 丄 2Vr determines the antenna factor afr for the receiving antenna. ⑽In free space, the load impedance of its antenna feed point Z0 = 50 Ω, and the input impedance of the antenna at the same operating frequency & Source v〇l When t is added to the feeding point of the transmitting antenna, the electric field generated by the transmitting antenna can be captured by the receiving antenna of the feeding point with a load impedance of ^ Ω terminal. r III-I · 515896 A7 B7 V. Explanation of the invention () NEC (Numerical Electromagnetic Code) electromagnetic simulation software determines the current L on the receiving antenna. Assuming that the transmitting antenna and receiving antenna of the same design are used at the same time, y = ^ _ x (z〇 + za)

^ A Suppose the current L νζ〇 X Rl in the dipole element is therefore [= 4 x (z〇 + D χ 1

^ A Z0xIL

For any transmitting antenna, s ′, its far-field electric field E (30 Ω rχ G) 2 d at a distance d in free space

Pf " radiated power G = antenna gain / 5 = 2π / λ, the wave number of free space is two wavelengths but PTT = Ι 2 χ RA, so the equation can be rewritten as follows: ^ / χ (30 ^ xG) 2 m · · d ................. (3) Refer to Figure 2 to describe the definition of the antenna receiving electric field E and the receiving voltage vr. The antenna factor (AF) is as follows: (Please read the precautions on the back before 1 ^ page j Bone Removal and Co-operation of Employees of Intellectual Property Bureau, Ministry of Economic Affairs & 515896 A7 B7 V. Description of Invention

Vr =

E AF and the effective length h is defined as

V2 h X E Therefore v h X AF current at 50Ω terminal j T 丄 1

V Z0 Z0xhxAF ....... ⑷ #We explain the effective length of the receiving antenna. The received power PR of the perfectly matched and lossless antenna is the incident field power density Wt and the antenna maximum. Product of receiving area Am. Pr = WT xAm 120; r 4π voltage at the load vR 120; Ra is the load impedance equal to the antenna's radiation impedance; the open circuit voltage of the antenna is equal to 2 times the receiving power, so the open circuit voltage should be V〇c, (please read the note on the back first) Matters on this page-installation line, · Member of the Ministry of Economic Affairs, Smart Finance 4 Bureau, TI Consumers, Titpli f0C '

Ε'χλ r Gx R π 120 y Definition of effective length h voc = h x E Therefore π 120; ⑸

= It can be seen that the simple effect length h is irrelevant to Ta Na, so there is a ratio of the length of the electric field between the political leader and her. Substitute by the equation ⑷ Office 方程 equation π πχπ, ion 〇〇 χ Gx i? X.

AF (6) Bring the equation 程式 to the w equation ⑶ νχπ

x 丄 x (3〇 ^ xG)]

AF d e Ίβά ⑺ e, Shun ^ AF x λ d

^ l ^ AF

2A y, e, 2A 5Z. x #, fM is the frequency in Maga Hertz j [F2 = 2 ^ xyx / MxA ^ 5z0xaf ^ r

AF = [2 ^ VxfM > < A

5Z0 x AF x. 'Ίβά d # (;), log ι〇ΐβ ^ χΑχβ ~ ^ V 5 ^ 〇 d

dB # (;) 40 l〇g10 \ ^ JlfMxAye- ^ dB 5 ^ 〇d AF (~ ^) z = 10 1〇Sl〇 | ^ 4ι, ^) 5Z0xj I 515 515896 A 7 ------- --B7 V. Explanation of the invention (2) Antenna phase center point The antenna phase center point is defined as the position of the antenna emitting radiation source. The position of the active element of the Radiation Elements of the log-periodic dipole antenna LPDA moves with the frequency scan. Therefore, the center point of the antenna phase will change position with different frequencies, which will cause the distance between the transmitting antenna and the receiving antenna to be incorrect. No matter how the information needed to calculate the antenna factor from the field attenuation requires the distance between the antennas. Therefore, if the distance between the antennas is selected to be fixed, this will result in an error in the estimation of the antenna factor due to the error caused by the frequency change. In order to achieve the minimum uncertainty requirement of the LPDA antenna factor correction, the distance error must be corrected. Reduced to a minimum. The following describes three methods for calculating the phase center point of LPDA: Method 1: A single point where the far-field phase response of the transmitting antenna located on the linear axis of the antenna is printed with a symbol indicating that the transmitting antenna is located on the linear axis of the antenna. The method of position is called the minimum phase change center method. The description of the coordinate system is shown in Figure 3. 515896 Μ 5. Description of the invention --------- 丨 ·-^ 1 — (Please read the precautions on the back before Ij assume that the distance between point A and point B is the phase center point When the distances are the same, find the position of the phase center point as follows: Phase center point (Phase cenW) Er + y〇2-and 2 ...... (g) 2 (i? -X〇) Proof of the above equation As follows: Because A and B are at the same distance from the phase center point p (P + R) HP + Xq) 2 + Y〇2 P2 + 2PR + R ^ P2 + 2px〇 + x〇2 + y〇2 2PR-2PX0 = X〇2 + y〇2—r2 2P (RX〇) -X〇2 + Y02-R2 P (phase center point R2 2 (Rx〇) Printed by the 8th Industrial Cooperative Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs In Figure 2, it can be clearly seen that point A is a far-field condition located on the antenna's straight line, and B · "is a small distance from the linear axis of the antenna, and parallel to the linear axis of the antenna, and the phase center point P is located on the χ vehicle. Move to a certain point until point A and point B have the same phase.

515896 Intellectual Property of the Ministry of Economic Affairs, Boundary Industry Cooperative #Cooperative Stamp ¾ A7 ---___ B7 V. Description of the Invention () The log-periodic dipole antenna LPDA, which is used for reception, is an antenna element at the phase center point to receive any incident For electromagnetic waves, the Antenna Elements in the Active Region is equivalent to the length of a Resonant Half-Wave Dipole Antenna at the same receiving frequency. In general, the maximum current falls on the phase center point. Method 2: The maximum current distribution method uses numerical simulation of the moment method to calculate the maximum current of each radiating element on the antenna. Therefore, many times of NEC electromagnetic simulation software must be used to calculate the maximum current of each radiating element on the antenna at different frequencies. data. When the maximum current of the component corresponding to each frequency point is calculated, the relationship between the frequency point and the position of the antenna radiating element can also be drawn at this time. Since the position of the light emitting element of the LpDA antenna has discontinuous innate characteristics, its curve Stepwise. Method 3: Interpolation method The method is based on the electric field strength ratios calculated by the antennas at different measurement distances, and then the phase center point is taken longer. The NEC electromagnetic simulation software can calculate the off-radiation (please read the precautions on the back before this page — ^-install--! = 1 I! I-I-· I-i--i · 11 515896 A7 B7 5 、 Explanation of invention (Electric field strength E at any distance of the antenna; its step 1 is assuming that Xi is far from the transmitting antenna (at this distance \, the LPDA antenna has its phase center point can be assumed not to change with distance), calculate Its electric field strength E1, its step 2 is to get closer to the transmitting antenna (1 meter or 2 meters), but it needs to be at least greater than half a wavelength away from the front end of the antenna. The ratio of the radiated electric field can be simply and quickly determined by the following equation Calculate the position of the phase center point d (m) = MlzMi · Ε2-Ελ The proof of this formula is as follows: Since Εγ · 1 E2〇c- (10) (please read the precautions on the back first) and then X 2 ^ E2 ~ X ~ ^ dd Ministry of Economic Affairs «Property Bureau From: Gong Consumer # Cooperative Society Seal ^ Order less R + R: E2 X ^ dR (Xi + d) = X2 + dRX「 X2 = d-Rd = d (1 -R) Ελχλ -e2x2

As shown in Figure 4, the method used in this article is still assumed to be in free space 纛 515896 A7 B7 V. Description of the invention (please read the notes on the back first and then the page), use two identical antennas to perform NEC numerical simulation. One of them serves as a transmitting antenna 41, and the other serves as a receiving antenna 42 at a position d at an arbitrary distance from the transmitting antenna. In order to compare the difference between the computer simulated antenna factor and the measured antenna factor, a method for accurately calculating the distance d between the phase centers of the two antennas has been provided in this article. There are three methods for different test frequencies to choose from, but in fact each method has Very small errors exist. A voltage source V is added to the feeding point of the transmitting antenna, and the generated electric field is captured by the feeding point with the touching antenna terminated by Zhenjie ZG (50Ω), and the & amp of the transmitting antenna can be calculated by NEC computer numerical simulation. ; Impedance and receiving antenna current IL. So the equation can be expressed as follows: 0 Site attenuation A (dB > 20 i〇gl () | & (ζ〇 + Λ1χ— 1-Printed by JAV ^ T Cooperative, 4th Bureau of Smart Finance, Ministry of Economic Affairs ¾

UA Z0 x IL antenna factor must (,) = 10 1〇giQ 丨 2 ^^ 丨 + qin) 5Z0 xd 2 In general, the measurement broadband proposed in this case lies in placing the broadband antenna on the radio wave Hitachi official website. Hit the characteristic number i 撼; ^, / ~ 9 miles into the shellfish test, and then simulate with the computer to avoid unnecessary high reliability data. At the same time, because the test environment is simple, and inflammation, the test results have less uncertainty 515896 V. Uncertainty. In addition, Shi’an An ^ 作, the practice is customary, but the above-mentioned embodiment is still sufficient to cover the application of the second patent of the technology in this case.范围 The scope of patent application is as follows (please read the precautions on the back first, then 2

--3 --- line printed by Xiao Gong Consumer Cooperative, Bureau of Intellectual Property, Ministry of Economy

Claims (1)

515896 Sixth Intellectual Property Bureau of the Ministry of Economic Affairs Employee Cooperative Cooperative 卬 Λ8 B8 CS 08 Application for Patent Scope 1. A method for measuring a wideband antenna, including the following steps: Approve a ft new room, which is interfered with by the electrical industry in the material industry. The field strength is ΐ, and a spectrum analyzer is used to verify the end of the wideband antenna ”, Ί, to obtain a first antenna factor (Antenna Factor); a computer simulation is performed on the wideband antenna to find a second antenna Factor; and comparing the first antenna factor and the second antenna factor to obtain a reliable antenna factor. 2. The method for measuring a wideband antenna as described in item 1 of Shenjing's patent scope, wherein the wideband The antenna system includes a biconical antenna (BicOnical Antenna), a log periodic dipole antenna (LPDA, Log periodic dipole array), a dual logarithmic antenna (βb 10g Antenna), and a spiral antenna (spiral antenna). The method for measuring a wideband antenna as described in item i of the patent application, wherein the anechoic chamber is a closed space constructed with an absorbing material, and it may be an EM Cell or GTEM Ce ll. 4. The method for measuring a wideband antenna as described in item 1 of the scope of patent application, wherein a field strength tester with an uncertainty of one tenth of the uncertainty of the antenna under test should be used to make a positive determination. Electric field strength in an anechoic chamber. 5. The method for measuring a broadband antenna as described in item 1 of the scope of patent application, wherein the computer simulation method is a method of Moments, Numerical Analysis for EM Fields) 〇6. The method for measuring a wideband antenna as described in item 5 of the scope of patent application, wherein the computer simulation method of the electromagnetic method of the moment method can further obtain a field attenuation (Norma 1 ized Si Attenuation) and an antenna phase center Phase Center 7. The method for measuring a wideband antenna as described in item 6 of the scope of patent application, wherein the phase center point of the antenna is obtained by including a minimum phase change center method, a maximum current distribution " TT Read the notes on the back again? Binding line 515896 ΛΒ CC Wai I, 巳 々 张 利 专 主 主 弓 --α in the sixth method and Interpolation method. 8. The method for measuring a wideband antenna as described in item 6 of the scope of patent application, wherein the wideband antenna is a wideband antenna that can be used for electromagnetic compatibility (EMC) detection. Ministry of Economic Affairs, α, _) Property Bureau_Industrial Consumption φ / it