received by the International Bureau on 24 August 2018 (24.08.2018)

1. An antenna arrangement (1) comprising:

- a printed circuit board (2) having a metallised area (3) acting as a ground plane (3) in use,

- a recess portion (4) in an edge portion of the ground plane (3), which recess portion (4) comprises a first side (13) and a second side (14), that are opposite to each other, a bottom base side (25) connected to the first (13) and second (14) side to form a periphery (5) of the recess portion (4) ending in two points (6,7) that form an opening (8) of the recess portion (4) in the edge portion of the ground plane (3),

- a first electrically reactive network (9) with two ports (10, 11) comprising a lump series capacitor component (12) there between, wherein the first reactive network (9) is bridging the recess portion (4) and having one port (11) electrically connected to the ground plane (3) on the first side (13) of the recess portion (4), and the other port (10) providing a radio signal feedpoint (15) at the second side (14) of the recess portion (4),

- a second electrically reactive network (16) with two ports (17, 18) comprising a lump series capacitor component (19) there between, wherein the second reactive network (16) is bridging the recess portion (4), separately from the first electrically reactive network (9), with one port (17) of the second network (16) electrically connected to the ground plane (3) on the first side (13) of the recess portion and another port (18) of the second network (16) electrically connected to the ground plane (3) on the second side (14) of the recess portion (4),

wherein the antenna arrangement (1) is configured to resonate as an antenna with a resonance frequency when a radio circuit (20) for transmission and/or reception of radio waves is connected to the feed point (15) and is receiving or transmitting radio waves at the resonance frequency,

wherein an electrical length of the recess portion (4), defined as the physical length from the opening (8) to a point on the periphery (5) of the recess portion (4) lying the farthest away from the opening (8) without crossing any ground plane (8) metal, is 1/10th of a wavelength of the resonance frequency of the antenna arrangement (1) or less, and wherein

a physical distance between the first (9) and second (16) electrically reactive networks (9,16) is less than 1/12 of a wavelength of the resonance frequency of the antenna arrangement (1) and characterised in that the shape of the recess portion (4) is triangular with the opening (8) of the recess portion (4) at one vertex of the triangle shape.

2. An antenna arrangement (1) according to claim 1, wherein the recess portion (4) has a shape with the base side being as long as a height of the recess portion (4) or longer, the height of the recess portion defined as the length of the shortest path between the bottom base side and the opening (8).

3. An antenna arrangement (1) according to any of claims 1-2, wherein the second electrically reactive network (16) is situated closer to the opening (8) of the recess portion (4) than the first electrically reactive network (9).

4. An antenna arrangement (1) according to any of claims 1-3, wherein the antenna arrangement (1) is 16 configured to resonate as an antenna with a further resonance frequency when a radio circuit (20) for transmission and/or reception of radio waves is connected to the feed point (15) and is receiving or transmitting radio waves at the further resonance frequency.

5. An antenna arrangement (1) according to any of claims 1-4 , wherein the reactance of the second 5 electrically reactive network (16) is higher than 100 Ω at a frequency of operation of the antenna arrangement (1).

6. An antenna arrangement (1) according to any of claims 1-5, comprising a radio circuit (20) for transmission and/or reception of radio waves connected to the feed point (15) and wherein the radio circuit (20) has at least one resonance frequency.

10 7. An antenna arrangement (1) according to any of claims 1-6, wherein the series capacitance of the first electrically reactive network (9) is in a range between 0.1 pF to 0.8 pF, preferably between 0.2 pF and 0.5 pF, and the series capacitance of the second electrically reactive network (16) is in a range between 0.05 pF to 0.6 pF, preferably between 0.07 pF and 0.4 pF, wherein the antenna arrangement (1) is suitable for operation in a range between 2 GHz to 6 GHz.

75 8. An antenna arrangement (1) according to claim 7, wherein

- the series capacitance of the first electrically reactive network (9) is about 0.3 pF and

- the series capacitance of the second electrically reactive network (16) is about 0.2 pF,

- a height of the recess portion is 3.5 mm,

- a breadth of the base side 25 is 8 mm,

20 at a resonance frequency of around 2.4 GHz, wherein the height of the recess portion is defined as the length of the shortest path between the bottom base side and the opening (8).

9. An antenna arrangement (1) according to claim 7, wherein

- the series capacitance of the first electrically reactive network (9) is in the range of 0.2 to 0.4 pF and

- the series capacitance of the second electrically reactive network (16) is about 0.07 pF,

25 - a height of the recess portion is 5.5 mm,

- a breadth of the base side 25 is 10 mm,

at a resonance frequency of around 2.4 GHz and a further resonance frequency of around 5 GHz, wherein the height of the recess portion is defined as the length of the shortest path between the bottom base side (25) and the opening (8).

30 10. An antenna arrangement (1) according to any of claims 1-9, wherein the physical depth of the recess portion (4) into the printed circuit board along a direction of the printed circuit board is 25% or less of the depth of the printed circuit board (2) in the same direction.

11. An antenna arrangement (1) according to any of claims 1-10, wherein at least a part of an electric line of the first electrically reactive network (9) is in a meandering form.

35 12. Device comprising an antenna arrangement (1) according to any of claims 1-11.