Planar transmission lines are structures that are made of thin conductive layers that lie in parallel planes and the propagating wave through them is doing that via a quasi-TEM mode. Knowledge of designing such structures is important if someone wants to make circuitry that works even on high frequencies. The PCB in this thesis was projected using two techniques of developing planar structures and these are called microstrip and coplanar waveguide. With the TVS diode as the primary component, other PCBs were projected too with a capacitor or a ferrite bead as the PCB's central element. Both the dimensions and the geometry were determined using KiCad's calculator, where values of various dimensions were compared so a wider frequency area would be covered. In this thesis, that means that for already specified values of PCB dimensions, only the length needed to be determined and in this case, the optimal value was to be as wide as possible. The mathematics behind designing and characterizing such a circuitry is not trivial. The easiest way to describing the behaviour of such circuits are S-parameters that are the defined as the square root of the power ratio of reflected and incident waves on certain ports. They were measured using a vector network analyzer on frequencies 300 kHz-8GHz and after examining the results, it was concluded that the PCBs work fine as far as the frequency is lower than 5 GHz if the demands are that the circuitry works until it reaches its higher upper frequency and that it is adjusted to 10 dB. TDR was used to determine impedance behaviour in the time domain, although only on the PCBs that have a TVS diode soldered to them using a DSO. Current-voltage characteristics of the PCBs with TVS diode were also measured using a semiconductor parameter analyzer and they turned out in according to expectations, which means that the conducting voltage and the break down voltage turned about to be of approximately the same amplitude between 7.2 V and 7.56 V. The final proof of the correct work of the TVS diode were meant to be measurements of the response on impulse disturbances but they could not have been conducted because of the inability to adjust the ESD pistol to generate high enough voltages.