Diamond match is a new type of antenna matching network suitable for matching single band antennas. It can not only match antenna impedance but also reduces the common-mode current to zero if only the horizontal antenna is symmetric and feeder is perpendicular to the antenna.
A short coax section and two capacitors are added near the antenna feed point, as shown below.
This version is suitable only for the antennas having its feed point impedance greater than 50 ohms.
This spreadsheet calculates the required capacitors Cs and Cp. Before using it, you need to measure the impedance of the diamond match at the frequency of interests and calculate it as the series connection of inductance Ldm and resistance Rdm as shown below.
Click here to download the spreadsheet to calculate the capacitors.