We have constructed an achromatic half-wave plate (AHWP) suitable for the millimeter wavelength band. The AHWP was made from a stack of three sapphire a-cut birefringent plates with the opticalaxes of the middle plate rotated by 50.5 deg with respect to the aligned axes of the other plates. The measured modulation efficiency of the AHWP at 110 GHz was 96 +/- 1.5%. In contrast, the modulation ef...

In this paper, a novel arrangement for dual-band millimeter-wave and infrared focal plane array based on slot-antennacoupled metal-oxide-metal diodes is demonstrated. The receiving properties for millimeter-wave and infrared antenna-coupled detector pixels are presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 78–80, 2005; Published online in Wiley InterScience (www.inters...

This paper describes recent progress of photonicallyenabled systems for millimeter-wave and terahertz measurement applications. After briefly explaining signal generation schemes as a foundation of photonics-based approach, system configurations for specific applications are discussed. Then, practical demonstrations are presented, which include frequency-domain spectroscopy, phase-sensitive mea...

The new Ka-band communications services require highly linear, high power amplifiers (HPAs). Traveling wave tube amplifiers (TWTAs) offer the best millimeter wave HPA performance in terms of power and efficiency, but are inferior to solid state power amplifiers (SSPAs) in linearity. This paper discusses techniques for improving millimeter wave HPA linearity. The significance and methods for eva...

We have constructed an achromatic half wave plate (AHWP) suitable for the millimeter wavelength band. The AHWP was made from a stack of three sapphire a-cut birefringent plates with the optical axes of the middle plate rotated by 50.5 degrees with respect to the aligned axes of the other plates. The measured modulation efficiency of the AHWP at 110 GHz was 96 ± 1.5%. In contrast, the modulation...

The applicabilty of superconductors to antennas is examined. Potential implementations that are examined are superdirective arrays; electrically small antennas; tuning and matching of these two; high-gain millimeter-wavelength arrays; and kinetic inductance slow wave structures for array phasers and traveling wave array feeds. Superdirective arrays and small antennas will not benefit directly, ...

A novel technique has been developed to generate ultra-stable millimeter-wave signal by optical heterodyning of the output from two slave laser (SL) sources injection-locked to the sidebands of a frequency modulated (FM) master laser (ML). Precise thermal tuning of the SL sources is required to lock the particular slave laser frequency to the desired FM sidebands of the ML. The output signals f...

A general formulation for the measurement of plasma density and effective collision frequency for lowly as well as highly, collisional plasmas using millimeter wave interferometry is presented. In the presence of high density and collisionality at high gas pressures where the collision frequency ~n! is of the order of both the plasma (vp) and the wave frequency of the millimeter wave ~v! (n ;v ...