Oct 1, 2007 #21 7 7rots51 Advanced Member level 4 Joined May 17, 2002 Messages 1,183 Helped 25 Reputation 50 Reaction score 12 Trophy points 1,318 Activity points 9,636 where can I find good design formula and calculations or software for Helical Filter at VHF(100~200 MHZ)? in LC filter design for pre-LNA applications what filter type and order is normally used?What is the min value of Q for L and C ?
where can I find good design formula and calculations or software for Helical Filter at VHF(100~200 MHZ)? in LC filter design for pre-LNA applications what filter type and order is normally used?What is the min value of Q for L and C ?
Oct 1, 2007 #22 V VSWR Advanced Member level 3 Joined Feb 7, 2002 Messages 746 Helped 103 Reputation 206 Reaction score 24 Trophy points 1,298 Activity points 5,423 http://tonnesoftware.com/helical.html **broken link removed** "Filters With Helical and Folded Helical Resonators" by Peter Vizmuller, Artech House, ISBN 0890062447
http://tonnesoftware.com/helical.html **broken link removed** "Filters With Helical and Folded Helical Resonators" by Peter Vizmuller, Artech House, ISBN 0890062447
Feb 9, 2008 #23 J james cook Member level 4 Joined Sep 4, 2005 Messages 72 Helped 25 Reputation 50 Reaction score 19 Trophy points 1,288 Location china Activity points 1,626 I think most of the filter for the front end system is the cavity filter assuming not very wideband.
Feb 10, 2008 #24 P peleda Advanced Member level 4 Joined Jan 10, 2006 Messages 110 Helped 22 Reputation 44 Reaction score 12 Trophy points 1,298 Location Monte Carlo Activity points 1,934 that frequency range may be too low for microstrips. Lumped elements should work fine.