Plasma Antenna

البلازما البلازما هي مادة موجودة بالكون كله تقريبا, وهي تعتبر شبه محايدة كهربائياً بمعنى أن الشحنة الكهربية تكاد تقترب من الصفر وهي خليط من الأيونات والإلكترونات وجسيمات محايدة (وهي ذرات غير متأينة) والبلازما ليست متأينة بالكامل ولكن لها قدرات تقنية قوية تمتد من إنارة الفلورسنت وحتى المعالجة في صناعة أشباه الموصلات, وتتفاعل البلازما بشكل كبير مع الموجات الكهرومغناطيسية.

يعتمد التفاعل ما بين البلازما والإشعاع الكهرومغناطيسي على الخصائص الفيزيائية للبلازما (الحرارة والكثافة) : فدرجة حرارة البلازما قد تبدأ من الصفر المطلق حتى تتعدى 10 9 كلفن. وكثافة البلازما تبدأ من أقل من جزيء بالمتر المكعب وتصل إلى كثافة أكثر من الرصاص.

المجال واسع لخصائص البلازما من المعامل المتغير والترددات فهو موصل للكهرباء, وتأثره بالموجات الكهرومغناطيسية ذات التردد البسيط مشابه للمعادن, يعني ببساطة أنه يعكس إشعاع الموجات البسيطة الطارئة. والمهم باستخدام البلازما هو التحكم بالموجات الكهرومغناطيسية المرتدة من الجسم (التخفي البلازمي) وهو عملي جدا بالترددات العالية حيث قابلية البلازما بالتوصيل تسمح بالتفاعل بقوة مع موجات الراديو القادمة ولكن تلك الموجات ستمتص وتتحول إلى طاقة حرارية بدلا من انعكاسها.للكهرباءالراديوطاقة حرارية بما أن البلازما يتماشى مع مجال واسع من الموجات, ففي حالة البلازما غير الممغنطة أكثر مايتصل بها هي البلازما المتذبذبة موجات لانجمير التي تتطابق مع الضغط الديناميكي للإلكترون. أما البلازما الممغنطة فهناك صيغ متعددة من الموجات ممكن اثارتها ممايمكنها من التفاعل مع اشعاع ترددات الرادار.للإلكترون

Plasma antenna A plasma antenna is a type of radio antenna currently in development in which plasma is used instead of the metal elements of a traditional antenna. A plasma antenna can be used for both transmission and reception. Although plasma antennas have only become practical in recent years, the idea is not new; a patent for an antenna using the concept was granted to J Hettinger in 1919.

Early practical examples of the technology used discharge tubes to contain the plasma and are referred to as ionized gas plasma antennas. Ionized gas plasma antennas can be turned on and off and are good for stealth and resistance to electronic warfare and cyber attacks. Ionized gas plasma antennas can be nested such that the higher frequency plasma antennas are placed inside lower frequency plasma antennas. Higher frequency ionized gas plasma antenna arrays can transmit and receive through lower frequency ionized gas plasma antenna arrays. This means that the ionized gas plasma antennas can be co-located and ionized gas plasma antenna arrays can be stacked. Ionized gas plasma antennas can eliminate or reduce co-site interference. Smart ionized gas plasma antennas use plasma physics to shape and steer the antenna beams without the need of phased arrays. Satellite signals can be steered and/or focused in the reflective or refractive modes using banks of plasma tubes making unique ionized gas satellite plasma antennas. The thermal noise of ionized gas plasma antennas is less than in the corresponding metal antennas at the higher frequencies. Solid state plasma antennas (also known as plasma silicon antennas) with steerable directional functionality that can be manufactured using standard silicon chip fabrication techniques are now also in development. Plasma silicon antennas are candidates for use in WiGig (the planned enhancement to Wi-Fi, and have other potential applications, for example in reducing the cost of vehicle- mounted radar collision avoidance systems.radar

Operation :  In an ionized gas plasma antenna, a gas is ionized to create a plasma. Unlike gases, plasmas have very high electrical conductivity so it is possible for radio frequency signals to travel through them so that they act as a driven element (such as a dipole antenna) to radiate radio waves, or to receive them.  Alternatively the plasma can be used as a reflector or a lens to guide and focus radio waves from another source.

Advantages Plasma antennas possess a number of advantages over metal antennas, including: As soon as the plasma generator is switched off, the plasma returns to a non conductive gas and therefore becomes effectively invisible to radar. They can be dynamically tuned and reconfigured for frequency, direction, bandwidth, gain and beam width, so replacing the need for multiple antennas. They are resistant to electronic warfare. At satellite frequencies, they exhibit much less thermal noise and are capable of faster data rates.

Oil and gas companies worldwide increasingly rely on broadband wireless systems to provide affordable high data rate communications to locations that are prohibitive costly or impractical to reach with optical fibre or leased lines. These networks connect remote locations, large facilities, people and applications, carrying large amounts of business- critical information and M2M data from telemetry and SCADA systems. In order to be competitive in this challenging market, wireless equipment OEMs need to deliver systems that can be deployed quickly and easily in remote locations - ideally by non-technical personnel. In addition, these systems need to be robust and reliable, incorporating self-managing and self-healing capabilities. Plasma Antennas' smart selectable multi-beam antennas can be automatically aligned when a remote or nomadic network node is installed. Automatic alignment eliminates the need for manual aiming, significantly simplifying deployment and reducing CAPEX. In addition, selectable multi-beam antennas can be re-aligned dynamically, enabling wireless networks to self-organise whenever as traffic or interference patterns change, or in order to provide fail-over mechanisms. When deployed at base stations and relay nodes, the high-speed beam-to-beam switching provided by Plasma Antennas’ selectable multi-beam antennas enable efficient spatial-TDMA, resulting in substantial increases in overall network capacity and lower cost-per-bit.