Simulation, design and integration of 60 GHz Gallium Nitride transceiver into nano-ferrite circulator on-silicon CMOS substrate
In this work the design and integration of 60 GHz monolithic microwave integrated circuit (MMIC) transceiver using 0.15 um Gallium Nitride (GaN) Qorvo process that will support the Wireless Gigabit Alliance (WiGig)/802.11ad radio specifications will be presented. The wideband GaN Power Amplifier (PA) can operate at 60–65 GHz with output power of 27 dBm and large signal gain of 23.5 dB. The wideband Low Noise Amplifier (LNA) has a small signal gain of 16 dB with a noise figure (NF) of 1 dB. The GaN PA and LNA are integrated to a nano-ferrite on-silicon CMOS circulator to construct a single front-end transceiver module.
Millimeter wave hexagonal nano-ferrite circulator on silicon CMOS substrate
Hexagonal ferrites such as BaFe12O19 have very strong uniaxial anisotropic magnetic field and remanent magnetism. By employing these properties, magnetic devices can work in the tens of GHz frequency range without strong external magnetic field. The micro- and nano-sized hexagonal ferrite can be conveniently utilized to fabricate magnetic components integrated in CMOS integrated circuits. A circulator working at 60 GHz is designed and integrated into the commercial CMOS process.
Live birth in the Devonian period
The extinct placoderm fishes were the dominant group of vertebrates throughout the Middle Palaeozoic era, yet controversy about their relationships within the gnathostomes (jawed vertebrates) is partly due to different interpretations of their reproductive biology. Here we document the oldest record of a live-bearing vertebrate in a new ptyctodontid placoderm, Materpiscis attenboroughi gen. et sp. nov., from the Late Devonian Gogo Formation of Australia (approximately 380 million years ago). The new specimen, remarkably preserved in three dimensions, contains a single, intra-uterine embryo connected by a permineralized umbilical cord. An amorphous crystalline mass near the umbilical cord possibly represents the recrystallized yolk sac. Another ptyctodont from the Gogo Formation, Austroptyctodus gardineri, also shows three small embryos inside it in the same position. Ptyctodontids have already provided the oldest definite evidence for vertebrate copulation, and the new specimens confirm that some placoderms had a remarkably advanced reproductive biology, comparable to that of some modern sharks and rays. The new discovery points to internal fertilization and viviparity in vertebrates as originating earliest within placoderms.