Metamaterials are a hot subject in microwave technology these days. Much of the work I see is going on with the design of antenna structures or substrate materials, but the researchers at Duke University have designed and tested a microwave cloaking device that can almost completely "hide" a small structure from microwaves. While this is not new news, they have more recent work going on to apply this technology to sound waves.
The Duke cloaking device is a structure made up of copper rings and wires patterned on a fiberglass composite. The structure is designed to route the microwaves around the hidden object inside and greatly reduces it reflection and shadow. The Duke team developed a small cloak (less than five inches across) that would provide invisibility in two dimensions, rather than three to simplify the design and prove out the concept. The cloak includes strips of metamaterial fashioned into concentric two-dimensional rings, a design that allows its use with a narrow beam of microwave radiation. The precise variations in the shape of copper elements patterned onto their surfaces determine their electromagnetic properties. The cloak design is unique among metamaterials in its circular geometry and internal structural variation, the researchers said. Up until that time all other metamaterials had been based on a cubic, or gridlike, design, and most of them have electromagnetic properties that are uniform throughout.
The researchers set out to prove the concept by aiming a microwave beam at a cloak positioned between two metal plates inside a test chamber, and used a detecting apparatus to measure the electromagnetic fields that developed both inside and outside the cloak. They first show a beam of microwaves hitting a 2 inch metal cylinder and then hide the cylinder within the cloaking structure. By examining an animated representation of the data, they found that the wave fronts of the beam separate and flow around the center of the cloak. Here is a video that demonstrates it:
So the Rumulans may have arrived on Earth but we may not be able to see them. What other interesting work have you seen using metamaterials???
Tasks now available for your phone
A couple months ago, Tasks launched in Gmail Labs. Tasks lets you easily create and manage to-do lists right in Gmail. Now, you can access and manage your task lists from your phone, too. Just go to gmail.com/tasks in your mobile browser and log in. If you have a Google Apps account, you can go to mail.google.com/tasks/a/your-domain, replacing your-domain with your actual domain name.On most phones, you can view tasks, add tasks, and mark them as completed. The changes are automatically reflected in Gmail. If you have an iPhone or an Android-powered device, you can also add, edit, and delete entire lists as well.
Tasks for mobile is currently available in English (like the rest of Gmail Labs). Read more on the Gmail blog and check out the video below.
Best Buy's Giftag on App Engine
Built by Best Buy, Giftag is a gift registry add-on for FireFox and Internet Explorer that enables you to create a wish list and share it with others. The Giftag team first built a prototype of the application on another platform and went live on September 2008. About 10 weeks later, the team relaunched Giftag on App Engine just in time for Black Friday. Since then, they've been getting positive reviews from users about the product.
We're happy to share this video created by Jerry St. Sauver, Curtis Thompson, and Thomas Bombach, Jr., the development team behind Giftag. In this video, they share their thoughts on App Engine, their development experience, tips on getting started with App Engine, and finally a demo of Giftag in action.
To learn more about what the Giftag team is up to, check out the official Giftag blog.
To share your own experience using Google App Engine, tell us your story (or even your own video) in our developer forum.
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