Designing inductor in ADS: How to determine the parameters?

Hello everyone,

I'm wondering if there is any guideline for inductor design using microstrip? Currently, I'm using the smart component from ADS, but it is still unclear to me the relationships of trace width / spacing / segments' length with its frequency response. Any suggested reading?


Thank you,
Mario Young

There are lot of IEEE papers reflecting effect of W,S,DIN,DOUT,t on Quality factor, Inductance, parasitics etc.

Is this what you want?

I am attaching some info anywazs

hope this helps

Hemanshu

Really nice shares...

You wrote "microstrip" which implies a solid ground below. Do you want to design it on PCB or on chip ?

Hi folks,

Thanks for all your replies, these helped me a lot...

I found from a textbook (Radio Frequency Integrated Circuit Design, 2nd Edition, J. Rogers and C. Plett: Section 6.17 "Layout of Spiral Inductors") very clear explanation about it, the only difference is, as volkver mentioned, I'm using microstrip, but the book refers to on-chip inductors, so, that brought me another question: do I need to place ground shield in microstrip design? since I already have a big ground plane below the circuit. Thank you!

Some other good reference on spiral inductor can be found in books like:
Lumped_Elements_for_RF_and_Microwave_Circuits by Inder Bahl
Low_Power_VCO_Design_in_CMOS__Springer_Series_in_A dvanced_Microelectronic

The equations in the book are valid for inducturs that have no ground below. Solid ground below will decrease the inductance, because of eddy currents in the ground shield. The inductor is much "better" without the ground below.

For integrated circuits on silicon, with a conducting substrate, a patterned ground shield can be used to shield the inductor from the lossy substrate. The "trick" with that ground shield is that is has slots, and eddy current can not flow. However, it adds capacitance and lowers the self resonance frequency. It's a compromise, if you need to shield the inductor from a conducting substrate.

On circuit board, don't use any ground below your inductor. You don't need it. Without ground, you can build a better inductor.

Hi volker,

very informative post..

So are you suggesting to remove ground layer while simulating for inductance for example in HFSS?

I am note sure what your question is!?
If you need/want ground in hardware, also include it in the simulation. It will change results.

For mycw who seems to do PCB work, I would not use ground below the inductor.

I want to fabricate my inductor and presently i am using a Ground Layer in my HFSS model while simulating it. The inductor is planned to be used as LC tank element of VCO.

SO do I need to have a ground plane in simulation?

1. If you need/want that ground in hardware, you must also include it in the simulation.
2. If you need/want that ground in hardware, patterned ground shield is better than solid ground.

Thanks Volker for your reply :)