microwave engineering - CAD of RF. IIT delhi

ppt on microwave engineering

1. Microwave Transmission Lines

2. Transitions between CPW and Coaxial cable For a good transition it is important that the outer conductor of the coaxial cable be short connected to the two ground planes of the “CPW.” The center conductor of the coaxial cable is of course short connected to the center conductor of the “CPW.”

3. Connection with Microstrip Two transitions are possible between these two lines. The first one is indicated in figure. This transition is characterized as having the hot conductors of these two lines on the opposite surfaces of the dielectric substrates. The two hot conductors are connected together through conducting hole, called a “via hole.” With this transition, the two lines share the same ground layer.

4. Connection with Microstrip The second transition is indicated in figure. This transition is characterized as having the cold conductors of these two lines on the opposite surfaces of the dielectric substrates. It is important that the ground conductor be connected together at the same potential. The two cold conductors are connected together using “via holes.” With this transition, the two lines share the same hot conductor. Note the tapering for the cold conductors.

5. Connection with Slot Line This connection is the most simple since both the “CPW” and slot line are uniplanar lines. For this reason, “CPW- slotline ” transition is currently investigated to improve performances . This transition has the characteristic that the signal coming from the slot line doesn’t excite the fundamental mode toward the “CPW” while the fundamental mode coming from the “CPW” cannot propagate toward the slot line.

6. CPW Directional Coupler The narrow shunt lines connected to the lateral ground planes represent a shunt inductance while the connecting lines perform a impedance transformation. CPW BPF

7. Slotline Discontinuities

8. Even mode Odd mode

9. Microstrip-to- slotline cross junction transition

10. Microstrip-to-CPW Transitions

11. Discontinuities in CPW Open circuit discontinuity Short circuit discontinuity