| View previous topic :: View next topic |
| Author |
Message |
gelunmak
Antenna Theory Regular
Joined: 05 Jun 2009
Posts: 17
Location: Hong Kong
|
 Posted: Fri Jun 12, 2009 10:34 am Post subject: Antenna Quality Factor (Antenna-Q) |
 |
|
Is the Q-factor important in antenna theory?
What's is defination & equation of Antenna-Q?
Is it Q=fc/(f2-f1)? [fc-center freq, f1 and f2 are cutoff freq]
What i understand is higher the Q, lower the bandwidth, and Q is defined as 2(pi) times the ratio of total energy stored to energy radiated per cycle. But i can only think of microstrip patch as a resonant cavity and apply the idea to patch antenna design. i.e. Increasing the substrate thickness --> increasing the radiated energy per cycle ---> decreasing the Q ---> Increasing Bandwidth! How Q related to other antennas?
Bty, not sure why there is a term " 2 (pi) " in the defination?
Thanks |
|
| Back to top |
|
 |
admin
Site Admin
Joined: 03 Jan 2007
Posts: 247
|
| Posted: Sun Jun 14, 2009 4:58 am Post subject: antenna Q |
|
|
In my mind, antenna Q only deals with bandwidth. However, equally valid is the interpretation you mentioned: the ratio of stored energy to energy radiated. Some antenna engineers think about Q from this second viewpoint; but not me.
The 2*pi factor in the definition is to make the two definitions numerically consistent. |
|
| Back to top |
|
|
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
