cmmb receiving terminal

Abstract

The invention relates to a China mobile multimedia broadcasting (CMMB) receiving terminal which comprises a CMMB receiving terminal main body and an antenna which transmits signal with the CMMB receiving terminal main body. The antenna is a metamaterial antenna which comprises a dielectric substrate, a metal structure, a feed line and a reference ground. The feed line is coupled with the metal structure in a mutual mode, and the reference ground comprises a first reference ground unit and a second reference ground unit which are respectively arranged on two opposite surfaces of the dielectric substrate. The first reference ground unit enables one end of the feed line to form a microstrip line. According to the CMMB receiving terminal, a topology form of the metal structure of the metamaterial antenna and reasonable arrangement of the microstrip line are accurately controlled, so that required equivalent dielectric constant and magnetic conductivity distribution are obtained. The antenna is enabled to realize good impedance matching in work frequency channels, and energy transition is finished efficiently, an ideal radiation pattern is obtained, and gain is high. In addition, the antenna is small in occupied size, and therefore the CMMB receiving terminal is small in entire size, and low in environment requirements.

Description

technical field [0001] The invention relates to the technical field of wireless access terminal equipment, in particular to a CMMB receiving terminal. Background technique [0002] The full name of CMMB is ChinaMobileMultimediaBroadcasting, namely: China Mobile Multimedia Broadcasting. CMMB is mainly oriented to small-screen handheld receiving terminals. Its terminal products mainly include MP4, MP5, mobile phones, GPS, USB receiving sticks, independent receivers, etc., providing digital broadcasting and TV programs, comprehensive information and emergency broadcasting services, and realizing satellite transmission and Seamless synergistic coverage combined with terrestrial networks. CMMB adopts mobile multimedia broadcasting and television technology with independent intellectual property rights. The system is operable, maintainable and manageable. It has broadcast and two-way service functions. It supports the operation system combining central and local governments. It h...

AI Technical Summary

Problems solved by technology

[0003] At present, the TV antenna of the CMMB receiving terminal is usually realized by an external telescopic antenna. However, the telescopic antenna is expensive, unattractive, and easy to be damaged when installed externally. Therefore, the built-in CMMB antenna is gradually used in the CMMB receiving terminal.

Since the U-band of the CMMB ground base station requires a frequency range of 474-798Mhz, it is difficult for the existing CMMB built-in antenna to meet the requirements of this frequency band, and the receiving capacity of the built-in antenna is much weaker than that of the external antenna.

Especially the lower frequency range of CMMB, 474-562Mhz, has always been a difficult point in antenna design. Even a rod antenna is difficult to achieve satisfactory reception indicators in this frequency band.

At present, in order to solve this problem, there are also some schemes that load the LNA circuit module to compensate the signal lost by the built-in CMMB antenna, but such design schemes have high requirements on the bandwidth of the antenna itself, that is, there is also a certain need for the size of the CMMB antenna. While amplifying the signal, it also amplifies the noise signal, and some frequency points may be submerged by noise, which deteriorates the CMMB receiving ability

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