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Questions related from John Jin
When measuring the radiation pattern in the E-plane and H-plane, it's common to rotate the measurement setup by 90° to capture the next plane. Now, consider a rectangular waveguide antenna...
03 June 2025 1,849 1 View
Hi, I have placed a coupling slot between two waveguides. In the main waveguide, where the input port is located, the coupling slot is positioned at the guided wavelength (λG/2) from the short...
12 December 2024 1,988 5 View
Hi, I would like to understand how to select the distance D in the array factor formula for two antennas, given by AF=2⋅cos(k⋅D⋅cos(a)). Here, D represents the distance between the two...
25 October 2024 9,136 2 View
Hello, 1) I simulated an open-ended WR-90 rectangular waveguide (F = 9.6 GHz, air-filled, L = 40 mm) in CST. According to the formula Zin=Z0cot(βL), the input impedance should be purely...
07 October 2024 7,113 4 View
Hi, I’m trying to determine the resonance length of a single radiating slot on a simple rectangular waveguide. Based on my understanding, the resonance frequency of an element can be identified...
06 October 2024 776 6 View
Hi, I have a rectangular waveguide(WR90) that operates at 9.6 GHz. Its guided wavelength is approximately λ_g = 42.34 mm, and the length of my waveguide is L = 950 mm. Calculation of S21...
01 September 2024 6,130 1 View
Hello, I am newbie to HFSS and I need to define the periodic boundary conditions on the upper faces of the wave guide that is clarified in the attached file. Could you please let me know how I...
19 May 2024 2,524 0 View
Hi, I get confused about the CST calculations for reflection and transmission values (S- S-Parameters) for different kinds of transmission lines. 1)First could you please let me know where is the...
03 May 2024 8,032 4 View
Hi, In the scheme, I want to define the two above faces as the periodic boundaries on Y axis. But as I defined it, the CST considers the maximum size of the total shape on Y axis as periodic...
03 May 2024 4,620 1 View
Hello, I need to simulate a quad-ridged waveguide in CST. At first, I set settings to excite the first six modes in the waveguide and I see the S21 for the first mode is less than -18dB at all...
21 January 2024 4,305 1 View
Hello, Here is my simulation regarding the WR90 waveguide dimensions. The S21 is acceptable and based on the waveguide theory it shows the right answer of cutoff frequency. But the S11 is very...
26 December 2023 6,823 3 View
Hello, I have some questions that I would be grateful if you could help me. 1) What is the difference between Horizontal and Vertical in 3D/1D far-filed radiation patterns?and 2) I know that the...
21 September 2023 2,716 0 View
Hello, I designed a reflector antenna that works fine when the feed is placed at a focal point with linear polarization. however, when I rotate the feed to 45 degree, I assume to get a 3dB loss in...
26 August 2023 5,284 2 View
Hello, I have a 2020 CST simulation file that was simulated one month ago. I've updated my CST to 2023 and added a new component to my simulation. But CST shows me this error: Components X: Y is...
14 May 2023 5,566 2 View
Hello, In different articles about reflector antennae, I see the writers provide feed source taper value( for instance in the level of -10dB to -15dB).I need to know how to obtain this value for...
24 March 2023 5,807 1 View
Hello, I just excited a parabola reflector antenna with a linear slant feed horn. So I have the vertical and horizontal planes for different polarizations. I need to know what the relationship is...
16 March 2023 8,262 5 View
Hello, I am doing sweep parameters in CST for my antenna simulation. As you know, during the sweep parameters procedure, the far-filed results are not available in CST and don't save and only the...
11 March 2023 2,458 7 View
Hello, Here are my settings for the phase center of my antenna. I need to know what are 1)The best values for Angular limit around Z' axis. 2)Phase center values in the left box? (0,0,58.45,...
13 February 2023 2,081 3 View
Hello, I need to plot SLL vs frequency in CST. I will be grateful if you could help me.
02 February 2023 994 0 View
Hello, I have two antennas (modem-microwave communication- Mikrotik) and I need to set them in the line of sight of each other for good quality(Best SNR) when they are located in different places...
19 November 2021 1,467 3 View
Hello, I need to know how to to design Butterworth filter with different insertion loss values. Regarding butterworth(Maximally flat) formula or table, they are obtained for insertion loss 3dB. I...
12 October 2021 6,386 4 View
Hello, I will be grateful if you could see attachment first. Based on the symmetry (Follow the "For example" in the first page up to end), I need to know why S13 is not equal to S31 (or S41 and...
01 October 2021 1,127 7 View
Hello, Regarding the CST documentation "However, the occurring broadband error may be prevented and the accuracy of the S-parameters improved with help of the inhomogeneous port accuracy...
18 September 2021 8,616 0 View
Hello, Here is my microstrip transmission line CST file which has been created by the Macro->calculated-> calculate analytical line impedance with these...
16 September 2021 5,384 4 View
Hello, I've attached my Bow-tie antenna-whose parameters is calculated by this site online calculator- project...
06 September 2021 1,303 6 View
Hello, I need to know why shorter impedance matching(IM) transmission line has higher Band width? (for example in designing IM circuit which has been calculated by Smith chart the shorter solution...
02 September 2021 2,296 10 View
Hello, I simulated a dipole antenna which is located vertically to the ground (the axis of antenna is z) in CST(Picture number 1). And the axial ration is calculated/plotted by CST as well(Picture...
24 August 2021 8,286 5 View
Hello, I was working with creating an antenna in CST but by adding a new material box above my antenna, I was faced with this error: The calculation domain is completely filled with metal (PEC)....
01 April 2019 4,722 3 View
HI all, I was going to loft two different faces but I have been faced with this error: Lofting Failed: face has more than one loop. I will be grateful if you help me.
23 March 2019 8,614 9 View
Hello, Based on my understanding for designing or analyzing an antenna radiation pattern, S11 and SLL are the most important parameters. However, I can't realized the role of E-plane and H-plane...
23 February 2019 1,050 36 View
Hello, I need to know why one of the famous solutions of the maxwell equation is called plane wave. Because based on the equation, should not it be a vector not a plane for example at t=0? what...
01 January 1970 4,300 1 View
Hello, I am an electrical telecommunication student who works on Antenna. I am very interested in IC design but I don't know how to learn it step by step. Do you mind to let me know the...
01 January 1970 4,801 3 View
Hello, I got confused when I've been face with different explanations about wave number and phase constant. Propagation constant=alpha+j Beta (Many textbooks, such as Balanis -advanced...
01 January 1970 8,493 7 View
Hello all, Based on a tutorial about meta-material I simulated the cell in CST software. However, some hidden aspects of this simulation is unknown to me. 1) Why did the tutor use waveguide port...
01 January 1970 3,002 5 View
Hello all, I am working on metramaterial these days,, and I got confused about Negative phase velocity and positive group velocity in metamaterials. I know how to obtain the equations but I can't...
01 January 1970 9,223 3 View
Hello, I need to know why having an electric current in Perfect Magnetic Conductor(PMC) violate current conservation. Based on the boundary conditions, I couldn't be successful to prove that...
01 January 1970 1,905 3 View
