This application is a 35 U.S.C. § 371 national phase filing of International Application No. PCT/GB2019/051249 filed on May 7, 2019, and claims the benefit of United Kingdom Patent Application No. 1901912.4 filed on Feb. 12, 2019 and of United Kingdom Patent Application No. 1807833.7 filed on May 15, 2018, wherein the disclosures of the foregoing applications are hereby incorporated by reference herein in their respective entireties.

FIELD OF INVENTION

This invention relates to antennae. In one form it relates to an antenna which is particularly suited for, but not limited to integration in an automobile. The antenna can be used to boost the signal strength of radio signals used in certain frequency bands. The antenna may, for example, find particular application for receiving/transmitting GSM or Wi-Fi signals or for receiving terrestrial television signals.

BACKGROUND OF INVENTION

In recent years, the growth in consumer electronics has been significant. Such consumer electronics includes, but is not limited to televisions, monitors, mobile telephones, smartphones, tablet computers, laptops, personal computers, portable games consoles, smartwatches and smart devices. As these devices become more prevalent in everyday left, there is a need for these devices to be capable of radio reception, but it for connection to the internet, another device, or merely to receive information. This need coupled with the trend to miniaturize these devices, be it for aesthetic and/or portability reasons, means that a wireless connection is the only viable option.

The conventional approach with most of these devices is to miniaturize the relevant receiving/transmitting antennae. The antennae are miniaturised to the extent possible whilst still enabling acceptable performance. However, what would pass as acceptable performance in ideal conditions can rapidly degenerate into unacceptable performance in real world use. For example, intermediate objects, neighbouring devices, signals, and antennae can mean that the strength of the received signal is poor at best, and the low performance of the antenna does little to improve the situation. This can result in dropped packets when the antenna is used for connection to the internet. In low bandwidth applications, this may not be noticed, but with the emergence of high-bandwidth applications (e.g. 720p, 1080p, Ultra HD television, game streaming services, etc.), a reliable, stable connection is necessary.

It is also common for these devices to have built-in cellular capability, where they connect directly to a base station of a cellular network. It is known that such devices can permit “tethering” to provide cellular-based WAN access (i.e. the internet) to a tethered device that would otherwise not be available. For example, many automobile systems (e.g. navigation software, voice queries) rely on the presence of a smartphone for internet access. However, a smartphone in an automobile may suffer severe cellular signal loss due to movement of the automobile and/or weak cellular signal strength.

An alternative solution is to use a dedicated antenna on the automobile itself to make the long-range connection to the cellular network. Typically, the dedicated antenna has much better performance characteristics than those of the existing antennae used in consumer devices. The superior performance characteristics of the dedicated antenna can alleviate the efforts of cellular signal loss.

Clearly, the choice of the dedicated antenna to be used cannot be made independently of the environment in which it is employed. For example, a dedicated antenna with a large “footprint” cannot easily be integrated into an automobile. Conversely, reducing the footprint of the dedicated antenna to assist with integration could only serve to frustrate the superior performance characteristics for which the dedicated antenna exists.

Hence, there is a need for an antenna that has high gain, low directional preference, but is low profile so that it can be used in a variety of environments.

According to the present invention there is provided an antenna comprising: a pair of electrically conducting first lands disposed in a first plane, the first lands being arranged to either side of, and spaced-apart from, an imaginary line on the first plane; antenna feed means for the pair of first electrically conducting lands; a pair of spaced-apart electrically conducting second lands, or a single second land, disposed in said first plane, said pair of second lands, or said single second land, being spaced-apart from the pair of first lands along said imaginary line, being electrically-insulated from the pair of first lands, and the pair of second lands being arranged to either side of, or the single second land extending across, said imaginary line; and a third conducting land oriented in a second plane substantially parallel to the first plane, wherein the first plane is spaced apart from the second plane by a value in the range of between 9λ/100 and 13λ/100 for an antenna operating frequency of between 700 MHz to 1100 MHz, or in the range of 14λ/100 to 18λ/100 for an antenna operating frequency of between 470 MHz and 800 MHz, where A is the wavelength of operation of the antenna.

The antenna in accordance with the invention offers two modes of operation in opposite boresight directions respectively. It can, dependent on the boresight direction, provide either lower gain over a wider bandwidth, or higher gain over a narrower bandwidth.

Preferably, the pair of first lands are arranged symmetrically about the imaginary line and/or the pair of second lands are arranged symmetrically about said imaginary line, or said single second land is symmetrical about said imaginary line.

Where the antenna is intended to operate at frequencies between 700 MHz and 1.1 GHz, the first plane is preferably spaced from the second plane by between 3 cm and 4.3 cm and more preferably 4 cm.

For operation in the above frequency range, the first and second lands are preferably arranged in a substantially rectangular configuration in the first plane, with the imaginary line extending in a y-direction in the first plane, wherein the distance between the outer edges of the pair of first lands in an x-direction in the first plane, perpendicular to the y-direction, is between 8 cm and 9 cm and more preferably 8.5 cm, with a gap between the each of the first lands in the x-direction of between 0.5 cm and 1 cm and more preferably, 0.75 cm.

The overall distance between opposite outer edges of the pair of first lands and the pair of second lands, or between opposite outer edges the first lands and the single second land, is preferably between 8 cm and 10 cm in the y-direction and more preferably, 9 cm, with a gap between the first lands and the second lands, or the single second land, of between 1 cm and 3 cm in the y-direction and more preferably 2 cm.

Alternatively, where the antenna is intended to operate at frequencies between 470 MHz and 800 MHz, the first plane is preferably spaced from the second plane by between 6.9 cm and 8.8 cm and more preferably by 8 cm.

Here, the first and second lands are preferably arranged in a substantially rectangular configuration in the first plane, with the imaginary line extending in a y-direction in the first plane, wherein the overall distance between the outer edges of the pair of first lands in an x-direction in the first plane, perpendicular to the y-direction is between 16 cm and 19 cm and more preferably 17 cm.

A gap between the first lands in the x-direction is preferably between 0.5 cm and 2 cm and more preferably 1 cm. The overall distance between opposite outer edges of the pair of first lands and the pair of second lands, or the single second land, is preferably between 16 cm and 18 cm in the y-direction and more preferably is 17 cm.

A gap between the first lands and the second lands, or between the first lands and the single second land, is preferably between 3 cm and 5 cm in the y-direction and more preferably is 4 cm.

The antenna, irrespective of which of the above mentioned frequency ranges the antenna is to operate at, may further comprising a fourth conducting land in a third plane substantially parallel to both the first plane and the second plane, offset from both first plane and the second plane, with the first plane located between the third and second planes, with the third plane preferably spaced apart from the first plane by a distance substantially equal to that by which the first plane is spaced from the second plane. The antenna may then provide an even higher gain over a narrower bandwidth

Where the antenna comprises a pair of second lands, preferably all of the first and second lands are substantially the same size and shape or have shapes which are mirror images of one another.

Where the antenna comprises a pair of second lands, preferably each land of the first and second lands is of a size and shape and has a spacing with respect to the other lands so as to permit resonance at the operating frequency.

Each land is preferably generally rectangular or trapezoidal, which allows the antenna to be easily scaled to a frequency of operation.

The third and/or fourth conducting land may comprise an electrically conducting panel of a device or of an object in which the antenna is mounted.

Where the antenna is mounted in an automobile, the panel may be a body part or a panel of the automobile and more particularly may be part of a wing mirror. Here, an outer surface or a backing of a mirror of the wing mirror may serve as the third land, with the first and second lands mounted within the wing mirror.

Alternatively the body part may comprise a panel of a metal door of an automobile or other object. Here the outer surface of the door may serve as the third land, with the first and second lands mounted within the door.

The third and/or fourth lands, and/or at least one of the first lands and/or the second land may be connected to an antenna ground and/or a system ground.

One or more of the second, third and/or fourth conducting lands, and/or one of the first lands may be connected to an antenna ground and/or a system ground. This can further improve the gain of the antenna.

