Patent Application
20090289854
This invention relates generally to communication devices, and more particularly to a method and system of forming an antenna using a stepped structure in a ground plane that can use existing radio feature architectures.
Existing antennas in radios or cellular phones having a wide range of requirements in terms of gain and bandwidth usually come in the form of an integrated stand alone structure inside the equipment or as standard patch antennas on a printed circuit board of the radio. Integration into a standard antenna such as a helical, monopole or patch antenna is not always possible or feasible, particularly for lower frequencies. Standard patch antennas are not big enough to perform properly to meet all the requirements in terms of bandwidth and gain. Further exacerbating the issues facing standard antennas are the trend for making radios smaller. The existing minimal volume antennas are usually components with high Q feeders or resonators that are deficient in terms of gain and bandwidth for current radio requirements. Some of the issues result from random ground excitation.
Embodiments in accordance with the present invention can provide an antenna assembly that comprises a stepped shaped in a ground plane that can utilize existing architectures such as functional knobs on radios to efficiently provide flexible and varied antenna performance with reduced overall volume.
In a first embodiment of the present invention, an antenna assembly in a radio can include a ground plane formed on a chassis of the radio where the ground plane has a stepped shape forming an antenna element, a notch element in the ground plane substantially adjacent to the stepped shape or in the stepped shape and having length less than ¼ wavelength, and a coaxial cable feeding the antenna element. A shield of the coaxial cable can be directly connected to the ground plane and a center conductor of the coaxial cable can be directly coupled to the stepped shape to provide a galvanic connection for narrowband performance or alternatively the center conductor can be electromagnetically coupled to the stepped shape for wideband performance. The antenna assembly can create a zero volume notch type ground excitation. The placement and direction of the notch element determines a polarization and a radiation pattern of the antenna element. The antenna assembly can be formed for integrated multiple MIMO antennas within the radio with different polarization and radiation patterns. The notch element can be a very short notch element near the stepped shape that forms part of the ground plane. Note that the notch element can be excited in parallel to provide both a galvanic connection for narrowband performance and electromagnetically coupled to the stepped shape for wideband performance for at least two different frequencies. Further note that the stepped shape forms a portion of a functional knob for the radio and can overlap at least a portion of the chassis. In one variant, a galvanic connection can exist between the functional knob and the ground plane formed on the chassis of the radio where a shorting element forms the galvanic connection between the functional knob and the chassis for example. The functional knob can be a rotary switch for squelch or a knob for channel selection or a knob for volume selection. The antenna can have a coupling feed system without a mechanical connection between a body of the functional knob and the coaxial cable, where the functional knob is formed from the stepped shape forming the antenna.
In a second embodiment of the present invention, an antenna assembly in a radio can include a ground plane formed on a chassis of the radio, a functional knob for the radio further having at least a portion of the functional knob serving as the antenna element, a notch element in the ground plane of a predetermined dimension between the antenna element and the chassis, and a coaxial cable (the feed) feeding the antenna element and a shorting element. The antenna assembly can further include a galvanic connection between the functional knob and the central conductor of the feed for narrowband performance or an electromagnetic coupling between the functional knob and the central conductor of the feed for wideband performance or both. A galvanic connection can exist between the functional knob and the ground plane formed on the chassis of the radio. Further note that the functional knob can overlap at least a portion of the ground plane formed on the chassis of the radio. A shorting element can form the galvanic connection between the functional knob and the chassis. The function knob can be a rotary switch for squelch, for channel selection or for volume. The antenna assembly can have a coupling feed system without a mechanical connection between a body of the functional knob and the coaxial cable. Note that the chassis and the stepped shape forming a portion of the functional knob can be on a single plane.
In a third embodiment, an antenna assembly in a radio can include a ground plane formed on a chassis of the radio where the ground plane has a stepped shape forming an antenna element, a functional knob for a radio further having at least a portion of the functional knob serving as the antenna element, a notch element in the ground plane of a predetermined dimension between the antenna element and the chassis, a coaxial cable feeding the antenna element (the feed), and a galvanic connection between the functional knob and the feed for narrowband performance and an electromagnetic coupling between the stepped shape and the feed for wideband performance.
The terms “a” or “an,” as used herein, are defined as one or more than one. The term “plurality,” as used herein, is defined as two or more than two. The term “another,” as used herein, is defined as at least a second or more. The terms “including” and/or “having,” as used herein, are defined as comprising (i.e., open language). The term “coupled,” as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The term “suppressing” can be defined as reducing or removing, either partially or completely.
The terms “notch,” “slot,” and the like as used herein, can include a missing portion in a ground plane or a chassis of a radio containing a ground plane. A stepped element or portion as contemplated herein can serve as an antenna or radiating element that can be on the same plane as the ground plane on a chassis or can be slightly offset from the ground plane. The stepped element can form a portion of a functional knob of a radio such as a rotary knob for squelch, channel selection or volume, but is not necessarily limited to such functional knobs. The stepped element can also form a portion of a conventional antenna that can be connected to the chassis of a radio using an SMA connector for example. As contemplated, the stepped element can form any portion of existing radio architectures to provide additional function and performance as further described below.
Other embodiments, when configured in accordance with the inventive arrangements disclosed herein, can include a system for performing and a machine readable storage for causing a machine to perform the various processes and methods disclosed herein.
While the specification concludes with claims defining the features of embodiments of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the figures, in which like reference numerals are carried forward.
The antenna and antenna assembly described herein can be very small in comparison to other internal antennas and can be ten percent (10%) the size in volume. Furthermore, the antenna assemblies herein can also utilize or incorporate existing architectures or structures that are already found in radios to reduce the overall size and volume of such radios and thereby enables the antenna to outperform all other internal antennas. These antennas can enhance or complement the antenna type range and can be useful for police radios with function knobs such as channel selector or squelch or volume knobs. The alternative main antenna as the main parasitic element.
Referring to
Embodiments herein can be generally be used as internal antennas for portable or mobile radio equipment. Existing internal antennas in radio equipment are typically variations of a PIFA antenna with a volume inside of the equipment of approximately 0.10×0.15×0.15λ. The embodiments herein can significantly reduce the internal volume used in a radio by planting a small notch in a chosen point, with an (almost) plane structure of 0.15×0.05×0.02λ which is significantly less than the noted existing PIFA antenna.
This structure in accordance with the embodiments herein can be particularly applicable for cellular, GPS and 2.4 GHz antennas where today's handheld equipment is looking to decrease the it's volume. In modern cellular phones or handheld terminals, the location and type of the antenna used are important. Note that the embodiments herein can be used in a variety of configurations without deviating from the broad scope contemplated. For example, with reference to
With respect to
With respect to
As noted above, embodiments herein do not require a special volume inside or outside a radio unit, but instead can facilitate the use of an existing unit's architecture to accommodate additional elements without global changes in the mechanical parts and into the outside shape of a device. The antenna utilizes the difference between heights of the existing elements of the unit and overlapping of the elements. As such, embodiments herein can include the use of a body or portion of a rotary switch that has an overlap with the chassis (or main board) of a radio. The chassis (or main board) has a role of the ground plane with a notch. The bodies, namely the chassis having the ground plane and the stepped element or antenna can be located on the same value of the axis x or essentially on the same plane, although embodiments can also include slight offsets. In a typical embodiment, an inner conductor of a coaxial cable can be connected to the body rotary switch or stepped element where the outer conductor of the coaxial cable is connected to the chassis.
Referring once again to the antenna assembly of
In light of the foregoing description, it should be recognized that embodiments in accordance with the present invention can be realized in hardware, software, or a combination of hardware and software if software is use to control or detect physical connections or distances between certain claimed elements that can provide variation in antenna characteristics or performance. It should also be recognized that embodiments in accordance with the present invention can be realized in numerous configurations contemplated to be within the scope and spirit of the claims. Additionally, the description above is intended by way of example only and is not intended to limit the present invention in any way, except as set forth in the following claims.
