Directional Coupler in Nazca

[AleksandarK]

Dear developers,

I am wondering how can a Directional Coupler,

like in the picture above, be implemented in nazca?

I have the latest Nazca-Design package.

Thanks in advance.

[Xaveer]

Dear Aleksandar,

 

There are many ways to do this. The example below uses the built-in demofab cross-section. You can use a very similar implementation for your own technology, by following the cross-section tutorial https://nazca-design.org/implement-a-cross-section/. You can make your directional coupler into a building block and re-use it many times by encapsulating it in a cell and adding pins to it. Look at https://nazca-design.org/crate-bb-using-polygon/ for inspiration.

Here’s an example for the directional coupler, using sinebend curves.

import nazca as nd
import nazca.demofab as demo

with nd.Cell("Coupler") as coupler:
    # Upper arm
    demo.shallow.sinebend(distance=100, offset=-40).put(0, 50)
    demo.shallow.strt(length=20).put()
    demo.shallow.sinebend(distance=100, offset=40).put()

    # Lower arm
    demo.shallow.sinebend(distance=100, offset=40).put(0, -50)
    demo.shallow.strt(length=20).put()
    demo.shallow.sinebend(distance=100, offset=-40).put()

    # Add pins
    nd.Pin("a0").put(0, 50, 180)
    nd.Pin("a1").put(0, -50, 180)
    nd.Pin("b0").put(220, 50, 0)
    nd.Pin("b1").put(220, -50, 0)

coupler.put(0, 0)
coupler.put(0, -200, 10)

nd.export_plt()

Xaveer

[AleksandarK]

Thank you very much!

That solves my problems.

[Ronald]

To make it more robust Xaveer’s example can be parametrized and pins can be set by reference:

import nazca as nd
import nazca.demofab as demo

def coupler(length=20, sep=100, gap=20):
    with nd.Cell("Coupler") as C:
        # Upper arm
        u1 = demo.shallow.sinebend(distance=100, offset=-0.5*(sep-gap)).put(0, 0.5*sep)
        demo.shallow.strt(length=length).put()
        u2 = demo.shallow.sinebend(distance=100, offset=0.5*(sep-gap)).put()

        # Lower arm
        l1 = demo.shallow.sinebend(distance=100, offset=0.5*(sep-gap)).put(0, -0.5*sep)
        demo.shallow.strt(length=length).put()
        l2 = demo.shallow.sinebend(distance=100, offset=-0.5*(sep-gap)).put()

        # Add pins
        nd.Pin("a0", pin=u1.pin['a0']).put()
        nd.Pin("a1", pin=l1.pin['a0']).put()
        nd.Pin("b0", pin=u2.pin['b0']).put()
        nd.Pin("b1", pin=l2.pin['b0']).put()
    return C

coupler().put(0, 0)
coupler(length=40, gap=5, sep=50).put(0, 100, 10)

nd.export_plt()

Note that setting pins by reference can be done using the ‘pin’ keyword. This will automatically copy all pin properties to the new pin.

# p is pin
nd.Pin("a0").put(p) # set the new pin at the position of p
nd.Pin("a0", pin=p).put() # copy all properties of p and put it on the position of p

Ronald

[AleksandarK]

Thank you Roland. That is helpful as well!

[Author]

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