The development of a 835-900-GHz biasable funda- mental balanced mixer using planar GaAs Schottky diodes is pre- sented. The monolithic microwave integrated circuit integrates two planar Schottky anodes in a balanced configuration, stripline fil- tering elements, and on-chip capacitor on a thin GaAs membrane. At 850 GHz, double side-band (DSB) mixer noise temperature of 2660 K and conversion loss of 9.25 dB are measured, respectively, at room temperature. When the mixer is cooled to 120 K, the DSB mixer noise temperature and conversion loss improve to 1910 K and 8.84 dB, respectively. Index Terms—Cryogenic test bench, fundamental balanced mixer (FBM), monolithic microwave integrated circuit (MMIC), passive cooling, planar Schottky diode, submillimeter wavelengths, vacuum chamber.

A Broadband 835-900-GHz Fundamental Balanced Mixer Based on Monolithic GaAs Membrane

We experimentally demonstrate a microwave far-field image reconstruction modality with the transverse resolution exceeding the diffraction limit by using a single layer of highly nonlinear metamaterial. The harmonic fields of the nonlinear metamaterial surface allow the far-field propagation of wave fronts with spatial frequencies several times higher than that of the fundamental field. Near-field images can thus be mathematically recovered from the far-field patterns of the harmonic fields.

/pdf/harmonic-image-reconstruction-assisted-by-a-nonlinear-2yy4zuseez.pdf

Harmonic image reconstruction assisted by a nonlinear metmaterial surface

We successfully demonstrated pulsed high-peak-power millimeter wave generation using periodically poled lithium niobate (PPLN) under collinear phase matching. We fabricated 0.5-mm-thick PPLN with a 40 mm interaction length for generating 250 and 300 GHz waves. Pump waves with very close dual wavelength output from a KTiOPO4 (KTP) optical parametric oscillator had a pulse energy of 2 mJ, pulse duration of 15 ns, and wavelength around 1300 nm. Millimeter waves were generated successfully, and the highest peak power obtained was estimated to be about 0.1 mW. This value is sufficiently high for envelope detection using a Schottky barrier diode. An active imaging system in the millimeter wave range could be realized using such a pulsed emitter and a Schottky barrier diode array.

Pulsed High Peak Power Millimeter Wave Generation via Difference Frequency Generation Using Periodically Poled Lithium Niobate

Detection sensitivity of a frequency-modulated continuous-wave (FMCW) radar can be limited by transmitter noise leaking into the receiver. For submillimeter-wave radars relying on high harmonic frequency-multiplication factors N>>1, phase noise typically dominates this leakage because it is amplified by 20log(N). A feed-forward phase noise cancellation circuit can suppress the effect of this leakage. Here we investigate quantitatively how effective this cancellation can be, finding that it is limited by additive residual phase noise in the harmonic generation chain. These results drive the transmit/receive isolation requirement in submillimeter-wave radars.

Residual phase noise and transmit/receive isolation in a submillimeter-wave FMCW radar

As a tribute to individuals who have contributed significantly, and over many years, to the terahertz community, and as a guide and inspiration for those who are just beginning their professional association with this field of study, these transactions have included, on a regular basis, a series of biographical interviews with technical researchers who have appreciably impacted the THz community in a positive manner. In order to go beyond a strict technical review and to take better advantage of the information and commentary only available through a direct discussion, these articles take on a less formal style than the research articles that can be found within the remaining pages of the transactions. The Editor-in-Chief (EiC) has taken some leeway in this regard, for the benefit of communicating more fully the character, experiences, and historic circumstances that have shaped our community and set the directions for our collective research. As a further means of assuring that the true flavor and circumstances of the contributions are expressed in the text, all of the articles are compiled after a face-to-face interview. The final text is shared with, and often helped considerably, by comments from the subject of the article. The EiC, with the support of the IEEE MTT Publications Committee, has chosen to incorporate these biographical articles within the more formal technical journal because of the diversity of disciplines that make up the THz community and the prior absence of a single unifying publication with sufficient outreach to extend across the whole of the RF and optical THz disciplines. The EiC hopes you will enjoy the short diversion of reading these articles as much as he himself enjoys the process of composing them. This month we cross the Pacific to hear the story of a young electrical engineer from Japan who was so self-motivated, he used his mother's inheritance to cover the cost of attending the very first international THz symposium, held in Brooklyn, NY, USA, back in March 1970. Ever since that career forming decision to participate in something new and exciting, Professor Koji Mizuno has been an active contributor to THz science and applications. Back in 1970, the appropriate terminology was submillimeter waves. Nevertheless, the discipline spanned a very wide application base and attracted a diverse group of scientists, which included chemists, physicists, engineers and even one or two biologists. Professor Mizuno worked in all of these areas, and as we shall find, has been one of the staunchest supporters of our discipline, as well as a tireless ambassador that has helped to bring the science of THz to Asia and beyond.

Terahertz pioneers: A series of interviews with significant contributors to terahertz science and technology

The Schottky barrier diode remains an important device for detecting and mixing at terahertz frequencies, particularly in plasma diagnostics and atmospheric remote sensing. In plasma diagnostics, plasma density is monitored using a receiver with an IF typically below 10 MHz, thus it is critical to reduce low-frequency excess noise to improve sensitivity. We present here a submicrometer Pt/GaAs diode fabrication process that has resulted in a significant reduction in low-frequency noise over that of commercially available devices. Noise performance is optimized by establishing an even distribution of gallium and arsenic (stoichiometric surface) at the contact surface. The effects of different SiO/sub 2/ deposition and etching techniques are also compared. Diodes fabricated with the optimized procedure have exhibited a signal-to-noise ratio that is three times higher than that of commercially available diodes at 0.9 THz using an IF of 80 kHz, as well as competitive performance at 1.4 THz with an IF in the gigahertz range.

Reduced low-frequency noise Schottky barrier diodes for terahertz applications

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

M. Araki

Author Tools

Chat about Author

Papers

Reduced low-frequency noise Schottky barrier diodes for terahertz applications