Fig. 1 shows a mock-up antenna to evaluate the characteristicsof the dual-port MIMO antenna. The size of thePCB board is 60 100 1 mm3, and it is printed on thetop of an FR4 substrate. The overall antenna PCB circuitheight is 1.3mm, considering the SP4T RF switch componentsize (3mm 3mm 0.6mm) on the front side directionand voltage component size (2.1mm 2.1mm 0.7mm)on the rear side direction. The antenna patterns are located at the bottom of the front side of the PCB, and an SP4T RFswitch is mounted near the ground short pin of the antenna forimpedance switching. To keep a smaller volume, the CCSLand the signal port 2 are folded by 90 degrees perpendicularlyto the PCB board. The overall dimensions of the antenna are27.5 8 mm2 for PIFA part and 10 17.3 mm2 for CCSLpart. These dimensions are compact enough to t in mobilehandsets. To facilitate measurements, 50ohm-shielded semirigidcables with SMA connectors are connected to both signalfeed ports of the dual-port antenna as shown in Fig. 1 (a).DC bias circuitries and a Li-ion battery as a power supplyof SP4T are mounted on the back side of the PCB board asshown in Fig. 1 (b).