Programme for Research-Development-Innovation on Space Technology and Advanced Research – STAR

results 2014

Stage nr 3. Technological development and characterization


  1. Schottky cip diodes characterisation

Test Schottky diodes on cip have been fabricated.
First version of test structures with one Schottky diode/cip have been characterised

test structure layout

image of the test structure with contacts

I/V characteristic in linear scale

The second version of the test structures has two antiparalel conected Schottky diodes. The I/V characteristic in logarithmic scale is simetric shaped and the slope is slightly lower then the expected value, corresponding to a higher ideality factor.


Test structure with two Schottky diodes in antiparallel connection: (a) test structure layout (b) photo image of test structure with contacts (c) I/V characteristic in linear scale (d) I/V characteristic in logarithmic scale

Monolithicaly integrated receiver

A direct detection receiver with a Schottky diode integrated with two folded slot antenas suspended on a thin GaAs membrane has been designed.

Layout for the monolithic integrated receiver (diode integrated with double folder slot antenna)

Photo image of the monolithic integrated receiver-detail of the thin GaAs membrane


                                (a)                                                     (b)
(a) Schottky diode monolithic integrated with antenaon GaAs membrane

(b) Schottky diode on thick substrate


                                                (a)                                                                                                        (b)

I/V characteristique for the receiving GAAS structure on thick substrate (mauve curve) on thin GaAs membrane (blue curve): (a) linear scale; (b)  logarithmic scale

Signal amplitude versus frequency

2. Integrated detector characterization at cryogenic temperatures

The hybrid integrated detector has been introduced in a cryostat and has been tested in dc and in microwave in the range temperature 18 K (– 255 C) şi 295 K (22 C).

Photo image of the hybrid integrated detector contacted on cryostat support



I/V characteristics measured in the temperature range 295 K and 23 K: (a) Linear scale; (b) detail in linear scale



3. Receivers with harmonic mixer

Layout of the harmonic mixer with coplanar waveguides

Manufactured experimental structure of the harmonic mixer with coplanar waveguides


                                        (a)                                                              (b)

HR-Si (a) Image of the circuits on HR-Si support; (b) Image of the mixer

Experimental results

Millimeter wave signals have been measured in the 88-98 GHz frequency band, OL signal frequency have been limited under RF signal frequency. The obtained FI signal was in the 2-8 GHz frequency range.


Experimental results obtained with the harmonic mixer with coplanar waveguides for three levels of the signal power: (a) POL = 8,8 dBm, (b) POL = 9,9 dBm, (c) POL = 10,9 dB., for fRF = 91GHz si fOL = 43.3GHz

A considerable signal improvement obtained with the mixer (at fFI = 4,4 GHz) with the local oscillator have been observed.


Experimental results: FI power dependence of OL power (a); conversion losses with the RF frequency dependence

Harmonic mixer with coplanar waveguide conversion losses variation with RF signal frequency for 10.8 dBm +/- 0.25 dB OL level. A good uniformity in the 89-96 GHz range is obtained.