Sensors for autonomous small robotic platforms must be low mass, compact size and low power due to the
limited space. For such applications, as the dimensions of the structures shrink, standard machining
methods are not suitable because of low fabrication tolerances and high cost in assembly. Commonly, the
structures show a high degree of fabrication complexity due to error in alignment, air gaps between
conductive parts, poor metal contact, inaccuracy in patterning because of non-contact lithography, complex
assemblies of various parts, and high number of steps needed for construction. However, micromachining
offers high fabrication precision, provides easy fabrication and integration with active devices and hence is
suitable for manufacturing high MMW and submillimeter-wave frequency structures. A radar design
compatible with micromachining process is developed to fabricate a Y-band high resolution radar structure
with a slot-fed patch array antenna. A multi-step silicon DRIE process is developed for the fabrication of
the waveguide structure while the slots are suspended on a thin oxide/nitride/oxide membrane to form the
top cover of the waveguide trenches and the patch elements are suspended on a thin Parylene membrane.
Gold thermocompression bonding and Parylene bonding are used to assemble different parts of the antenna.
These processes result in a compact (4.5 cm × 3.5 cm × 1.5 mm) and light-weight (5 g) radar.