Currently, countries in the world to promote the third generation mobile communication systems, while industrial, research focus has gradually Beyond 3G third generation of people after the> or the new generation of 4G mobile communication technology, wireless broadband communications technology, the research group aims to make wireless communications spectrum efficiency, capacity and rate of ten times or even a hundred times, which means that from now MBPS increased to the order of Gbps, which requires looking at the concepts and technology innovations and breakthroughs.

The spectral efficiency of wireless communication systems, information capacity and transmission rate developments, the proposed antenna more Gao requirements. From the initial mobile devices for portable whip antenna, and now dual-band compact handset antenna, the antenna towards the multi-band wideband, small size, high efficiency, low cost, easy integration direction. With the development of wireless communications, especially after future 3G and Ad-Hoc networks, in order to better improve communication performance against multipath fading and interference with adjacent users in the user terminals on demand has become increasingly smart antenna the more urgent. Some simplified smart antenna that new research and development, such as parasitic antennas and reconfigurable antennas transfer. In order to meet the harsh environment and limited wireless bandwidth spectrum high capacity mobile communications, data rate Gao, Gao coverage, high spectral efficiency, high reliability requirements, in recent years, UWB / SP wireless communication HP 4510s battery technologies has caused a great deal in the international of fever, one difficulty is that the design of ultra-wideband antenna; In addition, more than at home and abroad are being vigorously developed input multiple-output (MIMO) technology is also possible that one of the important technical breakthrough.

Below 7 on the multi-band mobile broadband terminal antenna, reconfigurable antenna, ultra wideband / short-pulse antennas, multiple-input multiple-output mobile terminal antennas for a description of developments.

1. Multi-band mobile broadband antenna justice

To enable communication systems to applications in multiple frequency bands simultaneously, including multiple communication frequency bands, the same communication terminal on a variety of wireless services, such as GPS, Bluetooth, WLAN and other services, multi-frequency / broadband antenna is the key issue. In addition, for a variety of commercial, civil and military needs, mobile communication terminals of conformal antennas, small size, Gao efficiency, low cost, easy integration into a new hotspot. As the antenna bandwidth, size, efficiency, and constraints are interrelated, and therefore taken into account how the three to find the balance point to achieve the best effect, is the design of mobile terminal antenna research focus.

2. Reconfigurable antenna

In the future 4G and Ad-Hoc and other wireless communication systems, wireless access to further enhance the system capacity and performance, has a smart antenna can be used, such as parasitic power transfer antenna. Parasitic tune the antenna is usually only one RF channel, but around the parasitic elements through the electrical resistance changes in the value loaded antenna in the whole plane to within a scan, a low-cost, simple system and so on. Parasitic tune the antenna is a reconfigurable antenna. Reconfigurable antenna, including frequency of reconfiguration, reconfigurable pattern, polarization can be reconstructed and also Lenovo Y650 battery has several characteristics of the antenna can be reconstructed, and its research unit involved in antenna, antenna array and control algorithms. In recent years, international conferences and academic journals which, on the reconfigurable antenna rapid increase in the number of articles, has received considerable attention, and its effective analysis and design theory a lot of work to be done.

Reconfigurable antenna is an important issue is to select superior performance to the antenna switch and integrated them. With the recent high-performance, low power micro-electrical mechanical (MEMS) switches and a number of GaAs PHEMT switches such as the emergence of technology, making the development of reconfigurable antennas have a better future. Switch is the ideal switching characteristics, a high isolation, low power consumption, easy to integrate. Now widely used in mobile communication performance of GaAs switches have also been significantly improved. 3. Ultra-wideband / short-pulse antennas (UWB / SP>

In recent years, ultra-wideband / short-pulse wireless communication technology in the international arena has caused a tremendous research interests. It has the energy in the home, office space and within a short distance to provide high-speed transmission, and without taking up additional spectrum resources and a series of advantages, so as to form personal networks (PAM) 8 and to meet strong global demand for greater bandwidth provided ideal way.

UWB / SP system to deal with the short pulse time domain signal, its spectrum covers a very wide, in order to ensure that the signal received by the antenna radiation and the time domain waveform is not distorted, which called for Gao fidelity, it is not only required for the antenna in the frequency domain UWB, but also to ensure that the antenna phase center with the same characteristics of UWB.

4. Multiple Input Multiple Output (MIMO) antenna next generation mobile communication technology, wireless broadband communications technology, the research group aims to make wireless communications spectrum efficiency, capacity and speed have increased tenfold or even hundredfold. Multiple-input multiple-output (MIMO) technology is probably one of the important technical breakthrough. Systems used in transmitting and receiving end of multi-antenna signal to control the spatial distribution, at the same frequency at the same time under the conditions of use of multiple antennas to provide parallel subchannels to increase system capacity or through spatial Toshiba NB200 battery diversity to enhance the quality of signal transmission Gao.

(1) adaptive MIMO technology.

MIMO technology is an important trend is adaptive multi-antenna technology. Traditional MIMO system requires the same number with the number of antennas the higher the price of RF transceivers. The adaptive MIMO system may use the number of RF transceivers less than the number of antennas with reconfigurable antenna MIMO system based on environment / channel automatically selected conditions, adjust the antenna elements used to obtain a small space correlation channels and large channel capacity.

(2) broadband multi-antenna technology miniaturization.

Mobile communication terminal by the mobile terminal multi-antenna systems, especially mobile phone measures only one wavelength or even smaller very strict restrictions, and require smaller antennas and seek with the mobile terminal equipment conformal. If we want such a harsh place multiple antenna size constraints and its corresponding control circuit Yi support adaptive techniques are in the Tian Xian unit, the control circuit miniaturization Tichu extremely difficult requirements. At present mobile communication systems and mobile personal communications systems used by the standard antenna structure is a monopole antenna or the built-in PIFA, the antenna is clearly unable to meet both the need for multiple antenna systems.

Therefore, mobile terminals, particularly in mobile terminals, on one hand required size of the antenna element itself to further miniaturization and high efficiency; the other hand, work to solve the original wide-band single antenna element in the application to multiple antenna system, after some band antenna unit of work becomes narrower, so as to achieve scale mobile broadband multi-antenna systems. In addition, mutual coupling between antenna elements ProBook 4515s battery Yi in isolation is a key indicator of the efficiency impact of the antenna, the antenna matching unit to be good, mutual coupling / isolation determine the antenna efficiency, but also the correlation between antenna elements and antenna The pattern, which directly affects the capacity of MIMO communication systems and quality.