Abstract: The present invention relates to an antenna stack comprising a ground plane and a plurality of antenna layers for separate operating frequency bands, the antenna stack comprising i) an antenna on one antenna layer and at least one antenna array on at least one different antenna layer or ii) at least two antenna arrays, each on a different antenna layer. Each individual antenna layer comprises an antenna or an antenna array that operates on a frequency band that is specific to the respective antenna layer and different from frequency band or bands of other antenna layer or layers. The antenna layer comprises antenna elements manufactured by patterning conductor material on a respective flexible and/or bendable sheet of insulating material. Antenna elements on the respective antenna layer is a circularly polarized crossed dipole antenna element or a crossed dipole antenna element that is electrically configurable into circularly polarized or linearly polarized configuration.

Abstract: According to an example aspect of the present invention, there is provided an antenna module comprising a Radio Frequency, RF, component electrical connection platform, a dipole antenna on top of, or buried in, the platform, wherein the dipole antenna is arranged to transmit and/or receive an RF signal and a distance between a ground at a bottom of the platform and arms of the dipole antenna is about a quarter of a wavelength of the RF signal and a pair of via holes comprising a first via hole and a second via hole extending through the platform, from the ground of the platform to the arms of the dipole antenna, wherein the first via hole is coupled to an RF feed and to a first arm of the dipole antenna and the second via hole is coupled to the ground at the bottom of the platform and to a second arm of the dipole antenna.

Abstract: According to an example aspect of the present invention, there is provided an antenna element for an antenna array, comprising, a transmission line and an antenna, wherein one end of the transmission line is coupled to a base board of the antenna array and another end of the transmission line is coupled to the antenna, and a first part of the transmission line is bent about 90 degrees compared to a second part of the transmission line, and the transmission line and the antenna are on, or in, a single flexible film.

Abstract: Apparatus and methods for matching the antenna of a radio device. In one embodiment, a capacitive sensor is arranged in the antenna structure and configured to detect the electric changes in the surroundings of the antenna. The mismatch caused by a change is rectified by means of the signal proportional to the sensor capacitance. This capacitance and the frequency range currently in use are input variables of a control unit. The antenna impedance is adjusted by means of a reactive matching circuit, the component values of which can be selected from a relatively wide array of alternatives by way of change-over switches, which are located in the transverse branches of the matching circuit.