SYSTEM AND METHOD FOR MEASURING ANTENNA RADIATION PATTERN IN FRESNEL REGION

• US 20090160706A1
• Filed: 04/10/2007
• Published: 06/25/2009
• Est. Priority Date: 04/10/2006
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Kim, Joung-Myoun, Yun, Je-Hoon, Oh, Soon-Soo, Moon, Jung-Ick, Cho, Yong-Heui
• Granted Patent: US 8,018,380 B2
• Time in Patent Office: Days
• US Class Current: 342/359
• CPC Class Codes: G01R 29/10 Radiation diagrams of antennas

Abstract

There is a provided a system for measuring an antenna radiation pattern in a Fresnel region, including: a fixed antenna and a movable antenna located in the Fresnel region to acquire a far-field radiation pattern; a moving unit for moving upward or downward to adjust a measuring angle of the movable antenna; a rotation unit to rotate a rotation shaft horizontally; a vector network analyzing unit for outputting an radio frequency (RF) signal to one of the fixed antenna and the movable antenna as a transmission antenna, receiving the RF signal received through the other one of the fixed antenna and the movable antenna as a receiving antenna, and detecting a complex value; a control and communication unit for controlling the vector network analyzing unit and a control unit, and performing a data communication; and the control unit for providing a vertical/horizontal rotation force to the moving unit and the rotation unit under a control of the control and communication unit.

Claims

1. A system for measuring an antenna radiation pattern in a Fresnel region, comprising:

a fixed antenna and a movable antenna located in the Fresnel region for acquiring a far-field radiation pattern;

a moving means moving upward or downward, for adjusting a measuring angle of the movable antenna;

a rotation means for rotating a rotation shaft horizontally;

a vector network analyzing means for outputting an radio frequency (RF) signal to one of the fixed antenna and the movable antenna as a transmission antenna, receiving the RF signal received through the other as a receiving antenna, and detecting a complex value;

a control and communication means for controlling the vector network analyzing means and a control means, and performing a data communication; and

the control means for providing a vertical/horizontal rotation force to the moving means and the rotation means under a control of the control and communication means.

2. The system of claim 1, wherein the fixed antenna is attached to the rotation shaft and the movable antenna is attached to a fixed shaft.

3. The system of claim 1, the movable antenna is attached to the rotation shaft, and the fixed antenna is attached to a fixed shaft.

4. A method for measuring an antenna radiation pattern in a Fresnel region, comprising the steps of:

determining a measuring parameter;

changing a measuring height by moving a movable antenna upward or downward;

measuring an antenna radiation by rotating a rotation shaft horizontally using the movable antenna at a predetermined height, acquiring a complex value and storing the acquired complex value in a database;

performing the step of measuring the antenna radiation by moving the movable antenna at all height; and

calculating a far-field radiation pattern.

5. The method of claim 4, wherein the measuring height of the movable antenna is acquired by a following equation 6 as:

Δ

h_m=R×

tan(Δ

α

×

|m|) 

 

Eq. 6

6. The method of claim 5, wherein in the far-field radiation pattern calculation step, the far-field radiation field is calculated by equation 1 based on a complex electric field value needed in the database, a Frourier coefficient of following equation 5, and compensation coefficients C_mm,D and C_mm,s of following equations 1 and 2 as:

$\begin{array}{cc}<br><br>E_{\mathrm{far}}<br><br>\left(\mathrm{\alpha <br><br>},\mathrm{\beta <br><br>}\right)=\underset{m=-M}{\overset{+M}{\sum <br><br>}}<br><br>\underset{n=-N}{\overset{+N}{\sum <br><br>}}<br><br>\left[\begin{array}{c}{k}_{\mathrm{mn}}·<br><br>E_D<br><br>\left(\mathrm{\alpha <br><br>}+m<br><br><br><br>{\mathrm{\Delta <br><br>}}_{\mathrm{\alpha <br><br>}},\mathrm{\beta <br><br>}+n<br><br><br><br>{\mathrm{\Delta <br><br>}}_{\mathrm{\beta <br><br>}}\right)·<br><br>\\ C_{\mathrm{mn},D}·<br><br>C_{\mathrm{mn},S}\end{array}\right]& \mathrm{Eq}.<br><br>1\\ <br><br>C_{\mathrm{mn},D}=\left(1+\mathrm{\Delta <br><br>}<br><br><br><br>R/R\right)<br><br>\mathrm{\angle <br><br>}<br><br>\left(\mathrm{\beta <br><br>\Delta <br><br>}<br><br><br><br>R\right)& \mathrm{Eq}.<br><br>2\\ k_{\mathrm{mn}}=\frac{1}{T_x<br><br>T_y}<br><br>{\int <br><br>}_{-T_x/2+a}^{T_x/2+a}<br><br>{\mathrm{<br><br>}}^{-\mathrm{<br><br>}<br><br><br><br>c_1^2<br><br>u^2}<br><br>{\mathrm{<br><br>}}^{-\mathrm{<br><br>}<br><br>\frac{2<br><br>\mathrm{\pi <br><br>}}{T_x}<br><br>\mathrm{mu}}<br><br><br><br>u<br><br>{\int <br><br>}_{-T_y/2+b}^{T_y/2+b}<br><br>{\mathrm{<br><br>}}^{-\mathrm{<br><br>}<br><br><br><br>c_2^2<br><br>v^2}<br><br>{\mathrm{<br><br>}}^{-\mathrm{<br><br>}<br><br>\frac{2<br><br>\mathrm{\pi <br><br>}}{T_y}<br><br>\mathrm{nv}}<br><br><br><br>v& \mathrm{Eq}.<br><br>5\end{array}$

where E_far denotes the electric field in the far-field region, and E_D denotes the electric field in a Fresnel region having a far distance D, and where k_mn denotes the Fourier coefficient, and a and b denote the coordinates of the center of the rectangular region having an amplitude of T_x and T_y, the C_mm,D denotes a compensation value to convert E_D into the electric field value E_R of a point far away as long as the same distance R, the C_mm,s denotes the compensation value for a first antenna, and Δ

α and

Δ

β

denote the increase/decrease value of the angle along the x-axis and y-axis directions.

7. The method of claim 6, wherein the cross sections M and N of equation 5 is calculated by using a correlation of an absolute value |k_mn| of the Fourier coefficient with the cross sections M and N, and is corresponding to the absolute value of the Fourier coefficient which is reduced as much as a predetermined Fourier coefficient from the maximum value of the absolute value of the Fourier coefficient.