Antenna coupling device

Abstract

The present invention relates to an antenna coupling device (14) for coupling radio frequency signal from a communication device (10) having an internal first antenna, the communication device (10) operable in n frequency bands, where n>1 and n is an integer. The antenna coupling device (14) comprises a port (16) connected/connectable to a transmission line (18). A conducting surface of said antenna coupling device (14) has a geometric shape in the form of a tree structure (20) connected to said port (16). The tree structure (20) comprises a number, m, of branches, where m≧n, wherein said tree structure (20) comprises at least one branch bix for each frequency band I of said communication device (10), wherein I is an integer and 1≦I≦n, and x is an integer and 1≦x≦k (i), and the total number, m, of branches satisfy the following expression ∑ i = 1 n ⁢ k ⁡ ( i ) = m wherein k (i) is a function of I, which only can obtain an integer value and is the total number of branches for frequency band.

Dependencies are inferred from the claim text.