Front-end characteristics Frequency bands : 1) 324-348 GHz (without H2O line 321 GHz) 2) 321-348 GHz (including H2O line). Expected receiver temp : 1500K(DSB) - 3300K(SSB) Fixed tuning : integrated design Schottky diodes mixer & HBV diodes tripler at ambient Temp. Brigthness temperature (K) Fol1 Fol2 Fol3 Fol3bis Frequency (GHz) 2 different scenario possibles

1st architecture scenario a single channel receiver head

2nd architecture scenario a dual channel receiver head

Generic architecture of a channel coupler Horn Subharmonic mixer LNA Tripler harmonic LO source (Gunn) PLL Reference Oscillator IF signal Spectral analysis module Antenna Coupler

Mixer design possibilities Subharmonic mixer cell using planar Schottky diodes pair (Univ. of Virginia) 1st design (400GHz UVa design) 2nd design (MIRO-like type) planar diode (UVa) :

Tripler design possibilities HVB diodes (InP based) tripler cell (IEMN- Lille) design (290 GHz tripler-like) Preliminary values : Freq. In : 56 GHz Freq. Out : 168 GHz Pin = 100-150 mW Pout = 10-15 mW n = 10% HBV diodes (8 barriers) :

Expected performances single channel receiver dual channel receiver

Sensitivity results single channel receiver dual channel receiver

Comparison between single/dual channel design Advantages of dual channel Better SSB receiver noise, Redundancy of the front-end (in case of failure). Drawbacks weight, space, power supply (price ?) increased Quasi-optical alignment more complex

Realisation context Baseline : Mixer development : Obs - Astrium - Virginia diodes Multiplier : Obs - IEMN - Astrium Low Noise Amplifier : Miteq, Chalmers LO source : Gunn : RPG - Farran PLL : Omnisys, Farran

Frontend-Mixer Schedule