Design of an Embedded Diversity Antenna for UMTS/HSDPA-Based Data-Card Applications

摘要

As a highly ambitious and complex radio standard, WCDMA is continuously adding new features to enhance its system specifications. One of the most significant additions to the WCDMA specifications is the corporation of high speed downlink packet access (HSDPA), in which technologies such as adaptive modulation coding (AMC) and hybrid automatic repeat request (HARQ) [1] are utilized to support data rate beyond 10 Mbps [2] in a 5 MHz bandwidth. As a result, the UMTS/HSDPA-based data card plugged into NB, PDA, or UMPC through standard interfaces, such as USB, PCMCIA, CF, or PCI_Ex, could be the one of a promising alternative to the seamless wireless communication standard to fulfill the concept of "Mobile-Net". There is a demand on compact flash (CF) data-card with high-speed downlink performance by employing UMTS/HSDPA-based technologies in some markets. To support the channel quality requirement, the mobile receive diversity (MRD) is proposed by Qualcomm platform [3] such that system uses polarization or angle diversity automatically adjusting the antenna characteristics to produce a near maximum received signal. However, the design of an embedded diversity antenna with acceptable envelop correlation coefficient is a challenge. In this work, we propose a meander-line mobile receive diversity (MLMRD) antenna design [4] in which a very compact meander folded monopole antenna is utilized as a primary antenna operating on bands of I, IX, and VIII and a PIFA is equipped on main PCB as an auxiliary antenna operating on Band I only. When operating, two antennas is located in a perpendicular orientation, resulting in good polarization and angle diversity to achieve low envelope correlation coefficient requirement within a very compact size (primary antenna: 4 × 34 × 5 mm{sup}3; secondary antenna: 30 × 1 × 4 mm{sup}3). To validate this approach, two types of antenna configuration are built for performance assessment.