MMIC Design and TechnologyMMIC Design and Technology

Instructor Dr. Ali Medi

Letcture 9 Mixers

Frequency TranslationFrequency Translation

( ) ( )11 ( ) ( ) )cos(21)cos(

21)cos()cos( tttt LORFLORFLORF ωωωωωω ++−=

)cos( tRFω( ) ( ) )(1)(1 tt ++( ) ( ) )cos(

2)cos(

2tt LORFLORF ωωωω ++−

)cos( tLOω

Letcture 9 Mixers

Reality due to NonlinearityReality due to NonlinearityConversion loss

dBIFoutputRFinputLC log10=

Typically 4 – 7 dB

Letcture 9 Mixers

Mixer DesignMixer Design

Again it is a matching exercise!

Letcture 9 Mixers

ExampleExampleShort circuit at 2nωLON=1,3,5,…

Short circuit at 2ωLOShort circuit at nωLON=1,3,5,…

λg is wavelength in the guide at the LO frequency

Single frequency circuit to terminate LO harmonics reactively

Letcture 9 Mixers

FET MixerFET Mixer

Letcture 9 Mixers

Single Ended FET ImplementationSingle Ended FET Implementation

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Dual Gate or 2 FETDual Gate or 2 FET

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Balanced FET MixerBalanced FET Mixer

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Dual Gate Balanced MixerDual Gate Balanced Mixer

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Double Balanced MixerDouble Balanced Mixer

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BalunBalun

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Resistive FET MixerResistive FET Mixer

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Double Balanced FET MixerDouble Balanced FET Mixer

Letcture 9 Mixers

Letcture 9 Mixers

Letcture 9 Mixers