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Nanoscale phase separation effects are of general interest in glass science. Such structural effects produce usually pronounced changes in glass physical properties which can mask the more subtle elastic effects related to rigidity transitions. The glass-transition temperature, Tg, is an intrinsic measure of network connectivity. It can be expected to increase or decrease as a network polymerizes or nanoscale phase separates. Compositional trends in Tg(x) in binary AsxSe1–x and GeySe1–y glasses show thresholds near the stoichiometric compositions, x = 2/5 or a mean coordination number r =2.4 , y = 1/3 or r =2.67 . These Tg trends in conjunction with spectroscopic (Raman, Mossbauer) evidence of broken chemical order suggest that the stoichiometric glasses As2Se3 and GeSe2 consist of a Se-rich majority phase that is separate from a compensating Ge- or As-rich minority phase, i.e., they are nanoscale phase separated. On the other hand, ternary Gex(As or P)xSe1–2x glasses containing equal proportions of the group IV and V elements reveal compositional trends in Tg(x) that increase monotonically with x; they appear to polymerize increasingly over a wide 2 r =2.40 . Previous claims of a rigidity transition near r =2.67 can be traced to nanoscale phase separation effects.

Molecular structure of GexS100-x glasses in the 30 < x < 34 atomic percentage range is examined by Raman scattering, 119Sn Mossbauer spectroscopy, and temperature-modulated differential scanning calorimetry. The results show that the stoichiometric glass with x = 33.33 (T g = 508°C) is chemically disordered. Raman scattering places mode strengths of corner-sharing Ge(S1/2)4 tetrahedra (A), ethane-like Ge2(S1/2)6 units (B), and the distorted rocksalt Ge(S1/6)6 units (C) at approximately 93.4:3.6:3.0 not normalized for mode cross-sections. Mossbauer spectroscopy places the concentration of these units as A : B : C = 76.2:8.8 :15. The drastic reduction in the slope of the glass transition temperature T g with Ge content x coincides with first appearance of these units once x exceeds 32.50, suggesting that these units are demixed and form separate nanophases to lower the global connectivity of the glass network.

In this paper, we describe an inductorless wideband radio receiver architecture from 1GHz to 10GHz. Two receiver RF frontends designs are presented and compared: a traditional inductor peaking LNA and mixer (IPLM) and a capacitive peaking LNA and mixer circuit (CPLM). Measurement results indicate that CPLM with the same bandwidth has better linearity, comparable noise figure and uses only 17% more power. The silicon area for the CPLM is only 22% of the IPLM. Both designs can be mated with an inductorless, ring-oscillator based, wide lock range and low power PLL also shown in this paper.

Inductors are used in RF design to extend the bandwidth by resonating out the load and/or parasitic capacitance. However, on-chip inductors are large and cannot be ported easily from one process to the next. Due to modern CMOS scaling, inductorless RF design is becoming possible. In this paper we describe a new methodology for designing the RF frontends necessary for the UWB 3.1GHz -10.6 GHz bandwidth in a 0.13 mum CMOS technology. To validate our design methodology two receiver RF frontends were designed; a traditional inductor based design and an inductorless design. A common-gate LNA transconductor is followed by a capacitive peaking LNA-mixer pair (CPLM). Simulation results show that a CPLM with the same bandwidth has better linearity, comparable noise figure and uses only 17 % more power. The silicon area savings for the inductorless LNA and I/Q mixers is roughly 90 % in comparison to traditional inductor based designs illustrating its compact size and improved portability.