Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Q value is negative of spiral inductor

Status
Not open for further replies.

myem

Full Member level 2
Joined
Dec 12, 2003
Messages
128
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,296
Activity points
986
I simulate spiral inductor by HFSS.
inductance is normal , indudctance equation=im(Zin)/(2*pi*freq)
but Q-value is negative , Q equation= Q=im(Zin)/re(Zin)
 

jeffreycheng

Junior Member level 2
Joined
Aug 14, 2006
Messages
22
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,435
Maybe, the frequency is beyond the self resonance and the inductor shows like a capacitor
 

FvM

Super Moderator
Staff member
Joined
Jan 22, 2008
Messages
48,914
Helped
14,335
Reputation
28,933
Reaction score
13,080
Trophy points
1,393
Location
Bochum, Germany
Activity points
282,243
Accoring to your equations, either re (Zin) must be negative (impossible for a passive circuit) or L would be negative, too. Apart from that, the Q equation would be valid only for a pure RL circuit, which is always in doubt for an inductor considering an extended frequency range.
 

LvW

Advanced Member level 5
Joined
May 7, 2008
Messages
5,853
Helped
1,745
Reputation
3,494
Reaction score
1,345
Trophy points
1,393
Location
Germany
Activity points
39,474
Perhaps you should go back to the original definition of the quality factor: Q=1/tanδ.
The angle δ is simply the angle between voltage and current of the inductor (which is zero for a lossless inductor)
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top