a diagram 300 illustrating return loss of the compact size antenna 10 according to an embodiment of the invention fig3 is utilized for illustrating measured return loss unit db over frequency unit mhz on the condition that energy or a signal is fed into the compact size antenna 10 via the signal feeding point 120 as shown in fig3 the compact size antenna 10 comprises operating frequency bands 31 32 according to the criterion set as 6 db in an embodiment of the invention the operating frequency band 31 covers from about 698 mhz to 960 mhz covering the lte700 gsm850 900 and the operating frequency band 32 covers from about 1710 mhz to 2690 mhz covering the gsm1800 pcs1900 wcdma band1 lte2700 therefore the compact size antenna 10 can meet frequency bands of 2g 3g lte communication systems the compact size antenna 10 can cover lte frequency bands except for u201c band 11 u201d and u201c band 21 u201d of lte communication systems in an aspect of antenna theory the radiation branch 121 may be excited to form a frequency point 311 in the operating frequency band 31 the connecting piece 15 the ground branch 132 and the metal arm 134 may be excited to form a frequency point 322 in the operating frequency band 32 the.