Line Calc

This section of the calculator has functions for the characterization of Rectangular and Cylindrical Cavities, Coax, Microstrip, Stripline, and Waveguide. Select the appropriate tab for the desired functions.

 

Waveguide

Selecting this tab the user can perform calculation for Waveguide by giving inputs of width, height, Dielectric Constant – Er and the wave mode to compute the rest. In addition, if the frequency of use is input then the full and quarter wavelengths are computed. I have defaulted to 1Ghz frequency input. Included in the calculations are the Cut-off frequency, the Upper and Lower Operating Range and the Velocity factor of propagation. By checking the PreDef Waveguide checkbox the user gets the calculations for all the predefined waveguide. Unchecking the box allows the user to input non-standard waveguide dimensions to calculate.

 

Figure 45 - Waveguide

Stripline

Selecting this tab the user can perform calculation for StripLine by giving inputs of trace width, trace thickness, height1 from lower ground plane, height2 from upper ground plane and Characteristic Impedance - Zo and Dielectric Constant - Er.  The user must input these and either the Er or Zo of these quantities and the program will compute the remainder and the velocity factor as a ratio of the speed of light. In addition, if the frequency of use is input then the full and quarter wavelengths are computed. I have defaulted to 1Ghz frequency input. By selecting the Asymmetrical check box the user can select between Asymmetric or Symmetric Stripline. In the case of Symmetric the Height1 and Height2 are equal and the Height2 prompt is invisible.

 

Figure 46 - Stripline

 

MicroStrip

Selecting this tab the user can perform calculation for MicroStrip line width, height from ground plane or Dielectric Thickness, Characteristic Impedance - Zo and Dielectric Constant - Er.  The user can input any three of these quantities and the program will compute the remainder and the velocity factor as a ratio of the speed of light. In addition, if the frequency of use is input then the full and quarter wavelengths are computed. I have defaulted to 1Ghz frequency input.

 

Figure 47 - Microstrip

Coax

This tab selection gives the user the functions to compute the characteristics of Coax Cable. The user can select from Predefined Coax types by checking the Defined Coax box or Custom Inputs by unchecking. The user can input his own variables in custom input mode. The four basic inputs are Inner Diameter (in), Outer Diameter (in), Dielectric Constant-Er and Characteristic Impedance-Zo. Input any of these three and Press the “Calculate Coax” button to compute the remaining fourth main element. The rest of the calculations are performed from the basic inputs and the Frequency Input. It computes the Cut-off frequency, Capacitance and Inductance per foot, the Time Delay, Velocity of Propagation as percent of light. With the frequency input it will add the calculation of full and quarter wavelength. I have defaulted to 1Ghz frequency input.

 

Figure 48 - Coax

 

Rectangular Cavity

This section gives an approximation for the rectangular cavity resonant frequency for unloaded, fully loaded (i.e. full of dielectric of a known Dielectric Constant) and a partially loaded Microstrip cavities. The user must input the cavity Length, Width, Height, the Dielectric Constant – Er and finally select from the pull down menu the Electric Field mode. I only support the Electric Field fundamental modes at this time, as these are the major modes used.

 

I currently provide the Empty Cavity and 3D resonant frequencies. The Er will determine the 3D case. If the Er is 1, then the 3D freq is the Empty case, if a Er of >1 is provided then the resonant frequency of the 3D cavity will be fully loaded. In addition I also calculate the Microstrip (partially loaded by addition of microstrip circuit boards inside the cavity. The first order is the empirical formula; the second iteration uses the first and the empty cavity case to determine an iterative solution for the Microstrip case. Also calculated is the Inductance and Capacitace for the cavity.

 

Press the “Calculate Cavity” to perform the calculation, “Clear” to clear the fields and reenter or “Close” to quit the screen.

 

Figure 49 – Rectangular Cavity

 

Cylindrical Cavity

This section gives an approximation for the cylindrical cavity resonant frequency for unloaded and fully loaded (i.e. full of dielectric of a known Dielectric Constant) cavities. The user must input the cavity diameter, length, the Dielectric Constant – Er and finally select from the pull down menu the Electric Field mode. I only support the Electric Field fundamental modes at this time, as these are the major modes used. Press the “Calculate Cavity” to perform the calculation, “Clear” to clear the fields and reenter or “Close” to quit the screen.

 

Figure 50 – Cylindrical Cavity