A mobile wireless communications device comprising: a portable housing; a substrate carried by said portable housing; wireless communications circuitry carried by said substrate; and at least one antenna assembly carried by said substrate and coupled to said wireless communications circuitry, and comprising: an electrically conductive base conductor comprising a first rectangular base portion and a second rectangular base portion offset therefrom, said first and second base portions (42a, 42b) being coupled at respective diagonally opposing corners thereof and having an antenna feed defined on one of the first and second rectangular base portions (42a, 42b), wherein the first rectangular base portion has a first side that is longer than a second side thereof, the second rectangular base portion has a first side that is longer than a second side thereof, and the first side of the first rectangular base portion is parallel to the first side of the second rectangular base portion; and at least one electrically conductive arm extending along both the short side of the second rectangular base portion that is furthest from the first rectangular base portion and the long side of the second rectangular base portion that is closest to the first rectangular base portion and spaced apart therefrom. a portable housing; a substrate carried by said portable housing; wireless communications circuitry carried by said substrate; and at least one antenna assembly carried by said substrate and coupled to said wireless communications circuitry, and comprising: an electrically conductive base conductor comprising a first rectangular base portion and a second rectangular base portion offset therefrom, said first and second base portions (42a, 42b) being coupled at respective diagonally opposing corners thereof and having an antenna feed defined on one of the first and second rectangular base portions (42a, 42b), wherein the first rectangular base portion has a first side that is longer than a second side thereof, the second rectangular base portion has a first side that is longer than a second side thereof, and the first side of the first rectangular base portion is parallel to the first side of the second rectangular base portion; and at least one electrically conductive arm extending along both the short side of the second rectangular base portion that is furthest from the first rectangular base portion and the long side of the second rectangular base portion that is closest to the first rectangular base portion and spaced apart therefrom. an electrically conductive base conductor comprising a first rectangular base portion and a second rectangular base portion offset therefrom, said first and second base portions (42a, 42b) being coupled at respective diagonally opposing corners thereof and having an antenna feed defined on one of the first and second rectangular base portions (42a, 42b), wherein the first rectangular base portion has a first side that is longer than a second side thereof, the second rectangular base portion has a first side that is longer than a second side thereof, and the first side of the first rectangular base portion is parallel to the first side of the second rectangular base portion; and at least one electrically conductive arm extending along both the short side of the second rectangular base portion that is furthest from the first rectangular base portion and the long side of the second rectangular base portion that is closest to the first rectangular base portion and spaced apart therefrom.