A Medium Power Solid State Amplifier for V-Band
A solid state amplifier for the 54 to 58 GHz band is described. The amplifier uses two layer InP Gunn devices. Three stages of amplification provide an output power of 100 mW at a gain of 15 dB. The small signal gain is 30 dB; the noise figure is in the 15.5 to 16.5 dB range. The design of a broadband low-loss V-band circulator, which was used in the amplifier, is also described.
Chapter 10 – Transferred Electron Devices
Publisher Summary 
This chapter begins with a discussion on transferred-electron diodes, or Gunn diodes. Gunn diodes are not true diodes because a “diode” is usually defined as a device having an asymmetrical current-voltage characteristic. As Gunn diodes possess a current-voltage characteristic similar to that of resistors, the terms “transferred-electron device” or “Gunn device” are more formerly used. The chapter reviews the Gunn device mechanism, fabrication technology, and applications. The chapter also provides an overview of negative differential mobility, device modeling, Gunn device design, and its fabrication. It explains the construction of various forms of Gunn oscillators and circuits. Gunn amplifiers and noise characteristics are also explored in the chapter. In the concluding part, the chapter describes the power-combining techniques of Gunn devices. Gunn diode oscillators have proved to be a reliable microwave and millimeter-wave solid-state frequency source. The GaAs Gunn diodes are used extensively in microwave and millimeter-wave systems from 3 to 120 GHz.
The Unusual Variability of the Large Magellanic Cloud Planetary Nebula RPJ 053059–683542
We present images and light curves of the bipolar planetary nebula RPJ 053059-683542 that was discovered in the Reid-Parker AAO UKST Hα survey of the Large Magellanic Cloud. The emission from this object appears entirely nebular, with the central star apparently obscured by a central band of absorption that bisects the nebula. The light curves, which were derived from images from the SuperMACHO project at CTIO, showed significant, spatially resolved variability over the period 2002 January through 2005 December. Remarkably, the emission from the two bright lobes of the nebula vary either independently or similarly but with a phase lag of at least 1 yr. The optical spectra show a low level of nebular excitation, and only modest N enrichment. Infrared photometry from the 2MASS and SAGE surveys indicates the presence of a significant quantity of dust. The available data imply that the central star has a close binary companion and that the system has undergone some kind of outburst event that caused the nebular emission to first brighten and then fade. Further monitoring, high-resolution imaging, and detailed IR polarimetry and spectroscopy would uncover the nature of this nebula and the unseen ionizing source.