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I have a 900MHz radio with a reference design matching network. The radio feeds to a PCB antenna (PCB antenna hasn't been verified with a VNA, and may not be a great match; this is a project to n...
Question
RF
#1: Initial revision
by
leroy105
·
2021-03-19T19:57:40Z (over 3 years ago)
Filter RF Harmonics With Additional PI Network
I have a 900MHz radio with a reference design matching network. The radio feeds to a PCB antenna (PCB antenna hasn't been verified with a VNA, and may not be a great match; this is a project to now fix this system). There are over the limit harmonics from the 6th harmonic (~5,400MHZ) to (~8,100MHz). The trace width of the antenna feed are (ostensibly) 50 ohms based on the board stackup. After the reference design matching network, we did put down an empty PI filter so I can add some additional filtering. Since we are trying to keep the impedance matched to 50 ohms, what is the best strategy to approach this circuit? Do you start with a low pass filter and then tweak the low pass filter to re-match as best as possible to 50 ohms?