Multi-section velocity compensated microstrip directional coupler
View Patent ↗A directional coupler having (a) a first coupled microstrip section having a first terminus (T 1 ) and a second terminus (T 2 ), (b) a second coupled microstrip section having a first terminus at T 2 and a second terminus (T 3 ), and (c) a first phase-velocity-compensating capacitor connected across the conductors of the microstrip sections at T 2 is disclosed. The coupler also may include a second phase-velocity-compensating capacitor connected at T 1 , and a third phase-velocity compensating capacitor connected across the conductors at T 3.
1. A directional coupler, comprising:
a first coupled microstrip section having two conductors extending from a first terminus (T 1 ) to a second terminus (T 2 );
a second coupled microstrip section having two conductors extending from a first terminus at T 2 to a second terminus T 3 ;
a first phase-velocity-compensating capacitor connected across the conductors at T 2 ; and
wherein the coupler has an isolated port that is internal to a housing of the coupler.
2. The coupler of claim 1 , further comprising:
a second phase-velocity-compensating capacitor connected at T 1 ; and
a third phase-velocity compensating capacitor connected across the conductors at T 3 .
3. The directional coupler of claim 1 , having more than one phase-velocity-compensating capacitor at a terminus of a coupled line section.
4. The directional coupler of claim 1 , wherein at least one of the capacitors is a multilayer surface mount capacitor.
5. The directional coupler of claim 1 , wherein at least one of the capacitors is a single layer capacitor mounted edge-wise between coupled line sections.
6. The directional coupler of claim 1 , wherein at least one of the capacitors is an integral part of conductors forming one of the microstrip sections.
7. The directional coupler of claim 6 , wherein the at least one of the integrated capacitors includes an air-filled gap between extensions of the conductors.
8. A directional coupler, comprising:
a first coupled microstrip section electrically connected to a second microstrip section at a junction, and
a phase-velocity-compensating capacitor connected across conductors of the microstrip sections at the junction; and
wherein the coupler has an isolated port that is internal to a housing of the coupler.
9. The coupler of claim 8 , further comprising:
a second phase-velocity-compensating capacitor connected across conductors of the first coupled microstrip section, but not across conductors of the second coupled microstrip section; and
a third phase-velocity compensating capacitor connected across conductors of the second coupled microstrip section, but not across conductors of the first coupled microstrip section.
10. The directional coupler of claim 8 , wherein at least one of the capacitors is a multilayer surface mount capacitor.
11. The directional coupler of claim 8 , wherein at least one of the capacitors is a single layer capacitor mounted edge-wise between coupled line sections.
12. The directional coupler of claim 8 , wherein at least one of the capacitors is an integral part of conductors forming one of the microstrip sections.
13. The directional coupler of claim 12 , wherein the at least one of the integrated capacitors is an air-filled gap between extensions of the conductors.