Wireless device and antenna system with extended bandwidth
A wireless device comprises a radiating structure that comprises a ground plane layer etched on a PCB, including a clearance area nearby one edge of the PCB, and an antenna element mounted on the clearance area. The radiating structure is included in a radiating system that also includes a radiofrequency system comprising at least a matching network, including more than three components. The radiofrequency system connects the antenna element to a feeding line connected at its end to an external port. The antenna element features a maximum length within the 22-30 mm range to match the radiating system in the multiple frequency bands of operation. In general, a radiating system features extended bandwidth, typically including LTE700 bands or below. The antenna element may include two conductive adjacent surfaces with a convex shape connected between them.
1. A wireless device comprising a radiating system that covers multiple frequency bands allocated in at least a first frequency region and a second frequency region, the radiating system comprising:
a radiofrequency system comprising at least a matching network that provides impedance matching to the radiating system at the multiple frequency bands; and
a radiating structure comprising:
an antenna element capable of transmitting and receiving signals in the multiple frequency bands and connected to a feeding line through the radiofrequency system; and
at least a ground plane layer,
wherein a maximum length of the antenna element is shorter than L/12 but longer than L/22, where L is the free-space wavelength corresponding to a lowest frequency related to a lowest frequency region of operation.
2. The wireless device of claim 1 , wherein the antenna element features a maximum length within the 22 mm to 30 mm range, the wireless device operating at a first low-frequency region ranging from 698 MHz to 960 MHz.
3. The wireless device of claim 1 , wherein a ratio between the lowest frequency of the second frequency region and the highest frequency of the first frequency region is greater than 1.2.
4. The wireless device of claim 1 , wherein the antenna element includes one or more conductive layers featuring a simple contour shape characterized by a complexity factor F 12 below 1.25.
5. The wireless device of claim 4 , wherein the contour features a rectangular shape.
6. The wireless device of claim 4 , wherein the antenna element includes a first large convex area adjacent to a second smaller convex area.
7. The wireless device of claim 4 , wherein the antenna element is placed on a ground clearance contained in the ground plane layer, the antenna element being combined with a conductive trace that connects it to the ground plane layer.
8. The wireless device of claim 7 , wherein a combined contour of the conductive trace together with the antenna element features a low complexity factor F 12 below 1.25.
9. The wireless device of claim 1 , wherein the radiating system comprises two or more ground plane layers.
10. The wireless device of claim 9 , wherein the ground plane layers are electrically interconnected one to each other.
11. The wireless device of claim 1 , wherein the radiofrequency system comprises a matching network that includes a plurality of stages comprising one or more circuit components, the stages being connected in series or in parallel with each other.
12. The wireless device of claim 1 , wherein:
the radiating structure, when disconnected from the radiofrequency system, features a first resonance frequency at a frequency higher than the highest frequency of the first frequency region, measured between the antenna element and the ground plane layer; and
a ratio between the first resonance frequency and a highest frequency of the first frequency region is greater than 1.5.
13. The wireless device of claim 1 , wherein:
the radiating structure, when disconnected from the radiofrequency system, features a first resonance frequency at a frequency higher than the highest frequency of the first frequency region, measured between the antenna element and the ground plane layer; and
a ratio between the first resonance frequency and a lowest frequency of the first frequency region is greater than 1.8.
14. The wireless device of claim 1 , wherein:
the radiating structure, when disconnected from the radiofrequency system, features a first resonance frequency at a frequency higher than the highest frequency of the second frequency region, measured between the antenna element and the ground plane layer; and
a ratio between the first resonance frequency and the highest frequency of the second frequency region is greater than 1.1.
15. The wireless device of claim 1 , wherein the radiating structure features a first resonance frequency placed within the 1200 MHz-1650 MHz frequency range, measured between the antenna element and the ground plane layer when the radiating structure is disconnected from the radiofrequency system.
16. The wireless device of claim 1 , wherein the radiating system features an impedance bandwidth in the first frequency region greater than 20% and in the second frequency region greater than 40%.