Bandwidth enhanced tri-band monopole slot antenna on ultra-thin metal housed devices

We present an bandwidth enhanced tri-band monopole slot antenna on metal housed devices which operates on GSM 850, 900, 1800, 1900 and UMTS band. The slots were place at the corner and the edge of the metal housed device in order to avoid the antenna performance degradation caused by ITO (Indium Tin Oxide) coated on display glass. Due to the location of the slot design and inherency of slot antennas, the bandwidth becomes extremely narrow, but this matter can be resolved by using extra parasitic monopole slots which are designed adjacent to the main slot. The measured results of the proposed antenna with the display module attached shows -6-dB bandwidth of 813 MHz to 993 MHz (19.6%) at the lower-band, 1.63 GHz to 1.99 GHz (19.89%) at the first-higher-band and 2.00 GHz to 2.24 GHz (11.32%) at the second-higher-band respectively and the lower band´s antenna gain varies from -2.29 dB to 0.11 dB whereas the first-higher-band´s gain and the second-higher-band´s gain varies from 1.90 dB to 3.80 dB and 0.16 dB to 3.02 dB respectively.