-uwb Phase Shifter

Aim of the project: The aim of the project is to design a 3-bit UWB Phase-shifter and implement one bit of it on a transmission line. Types of Phase Shifters: The Phase shifters can be grouped in two types. 1. Ferrite Phase Shifters 2. PIN diode phase shifters Ferrite Phase Shifters are activated by a pulsed current and power requirements are usually less than their PIN diode counterparts. Another issue that should be mentioned is that ferrite phase shifters are not reciprocal due to the characteristics of ferrite material. On the other hand, PIN diode phase shifters are smaller in size, integrable and have higher speed. Also circuitries implemented with PIN diodes occupy less area. However, diodes require continous voltage and bias current which increases power consumption significantly. Basic types of PIN diode phase shifters are switched line, loaded line and reflection based phase shifters. In my project I had chosen to use switched line phase shifter due to the following advantages: 1. They can be easily cascaded in order to achieve higher amount of phase shift by controlling the increments of bias voltage. In my project, phase shifter is 3-bit and it can increase the phase shift at an amount between 0 or eight times of a unit shift amount (it is actually approximately 200ps in my project and eight bits cause 1.6ns delay at most). 2. They are used in broadband systems because distortion is minimized. I was expected to build a circuit which would operate over a wide range of frequency values. 3. They have a considerable power handling capacity. 4. They are inherently reciprocal. 5. Insertion loss is determined by the loss of the switches and line losses. In this topology the amount of shifting is determined by the lenght of the transmission line. The losses in the line are due to the tangent loss of the FR4 and switching losses. As we know that although PIN diodes acts as short circuit when a certain potential difference between the nodes is exceeded, the amount of current is always limited to the amount of bias voltage. Thus there is always a resistance in the system in fact. But the resistance of the diode significantly reduces at higher voltage values. According to the measurements, the PIN diode available at our hand begins to conduct current of 0.5 mA when bias voltage exceeds 0.7 volts. After 1.2 volts amount …