Patent Application
20230092919
Embodiments described herein may be configured to provide an ultra-wideband antenna apparatus. In one embodiment, the apparatus comprises a monopole antenna portion formed on a first side of a printed circuit board; a ground pad formed on the first side of the printed circuit board and spaced apart from the antenna portion; and a capacitive ground structure-based matching structure coupled to the ground pad.
It is known in the art that broadband distribution networks, in particular cable TV (CATV) Hybrid Fiber-Coaxial (HFC) networks, commonly carry signals in their coaxial portions that may produce harmful interference to other adjacent electronic systems if allowed to radiate outside of the coaxial cable portion of the network. For instance, the FCC in the United States and Industry Canada in Canada have both had, for many years now, regulations governing the allowable “leakage” from the network of frequencies in the aeronautical VHF (very high frequency) radio band to help avoid known causes of air traffic control interference by terrestrial radiation sources. Furthermore, it is well known that other sources of terrestrial off-air radio signals like LTE (Long-Term Evolution) and other signals can intrude into the network (commonly referred to as ingress) causing signal degradation for the consumers of the HFC network's signals, which may cause anything from TV channel pixelization to reduced Internet speeds to consumers. The complexity and size of the distribution network require that network operation and performance be periodically tested and/or monitored.
Two tests often performed by CATV service providers are signal level monitoring and leakage detection. CATV service providers use signal level monitors to measure the signal level of particular channel frequencies at any part of the distribution network. For example, a technician connects the signal level monitor to the coaxial cable at any location within the distribution network. The signal level monitor allows the technician to obtain data regarding the frequency response of the distribution network and identify network-related signal transmission problems.
Leakage detectors are devices that detect and/or measure the leakage of CATV signals to the exterior of the coaxial cable. If the coaxial cable is insufficiently shielded, significant levels of the CATV signals may leak to the environment surrounding the cable. Government regulations permit only a finite level of coaxial cable leakage. Leakage detectors help determine compliance with government regulations and can otherwise provide information as to the performance of particular sections of a coaxial cable.
In one embodiment, the leakage detector may be part of a mobile leakage detector system mounted on and or within a vehicle. At a minimum, the mobile leakage detector system requires a wideband antenna to detect leakage signals within the desired frequency range of 250 MHz to 1220 MHz (1.2 GHz). Normally, a planar circular wideband monopole antenna with a 6 inch diameter can be used cover the 600 MHz to 1220 MHz range while a second, larger antenna with an 11.8 inch diameter can be used to cover the 250 MHZ to 600 MHz range. Therefore, in the conventional system, two antennas and a diplexer device are needed to cover the frequency range of 250 MHz to 1220 MHz. However, since the size of the two antennas are too big to be effectively mounted on a vehicle's roof, this system is not a good solution for a real world mobile application. The shortcomings of the two-antenna solution are compounded when an additional antenna and corresponding circuitry are required to detect leakage at frequencies below 250 MHZ.
Accordingly, there is a need and desire for a single and preferably compact antenna for a mobile leakage detector system that can be used to detect leakage signals within the frequency range of 250 MHz to 1220 MHz.
It should be appreciated that when developing an ultra-wideband antenna for the 250 MHz to 1220 MHz frequency range, the proper antenna size and peak gain should be considered. For example, an 8.5 inch diameter circular antenna may meet the frequency range requirements, but may experience a 5 dB return loss at approximately 250 MHz. This would adversely impact the antenna's gain performance. Since a 5 dB return loss will create a large mismatching loss and reduce the antenna's efficiency, a matching circuit could be considered to solve this problem. Theoretically, a narrow band matching circuit at 250 Mz could be used, but this circuit will create high-band mismatching issues. A wideband matching circuit, on the other hand, also is not desirable due to the difficulty of simulating necessary circuit elements resulting from the complex antenna impedance at the wideband range. Moreover, it is difficult to place a matching circuit at the antenna's output port, particularly for a mobile system.
In accordance with the disclosed principles, in one or more embodiments, a new matching structure comprising one or more capacitive ground structures (i.e., a “capacitive ground structure-based matching structure”) has been created to solve the low band mismatching issue described above. Each capacitive ground structure (CGS) comprises a conductive sheet (e.g., metal) having a particular size that is folded at a desired angle (e.g., a right angle) to form two portions. A first portion (e.g., a substantially vertical portion) of one or more capacitive ground structures is attached to the grounding pad of the antenna's printed circuit board (PCB) and another portion (e.g., a substantially horizontal portion) is mounted over and spaced apart from a metal reflector (e.g., a vehicle's metal roof when the apparatus is used in a mobile system) to create a distributed capacitance used for antenna matching. The capacitance value is determined by the size of the capacitive ground structures and the space between their horizontal portions and the reflector.
In one embodiment, the ultra-wideband antenna 100 may be a planar circular monopole antenna (PCMA) having an antenna portion 104, a co-planar waveguide (CPWG) 106 and an antenna output 108 formed on a first side of a printed circuit board 102. In one embodiment, a ground pad 110 is also formed on the first side of the printed circuit board 102. Details of the antenna 100 are discussed below with respect to FIG. 3. It should be appreciated that the disclosed matching structure 120 can be used on different shaped planar antennas, if desired.
Turning to
In one embodiment, the capacitive ground structure 130 may be bent or folded such that is has two portions, a substantially vertical portion 132 and a substantially horizontal portion 134. In the illustrated embodiment, the capacitive ground structure 130 is bent such that the substantially vertical portion 132 and the substantially horizontal portion 134 form a right angle with respect to each other. It should be appreciated that other angles can be formed depending upon the type and degree of antenna matching required.
In one embodiment, and as shown in
In one embodiment, the substantially vertical portion 132 may have a height H132 of 1.5 inches and a length L132 of 2 inches. In one embodiment, the substantially horizontal portion 134 may have a width W134 of 1 inch and a length L134 of 2 inches. In one embodiment, the thickness of both portions 132, 134 of the capacitive ground structure 130 may be 80 mils (i.e., 0.08 inches). It should be appreciated that the dimensions of the portions 132, 134 may be changed depending upon the number of capacitive ground structures 130 utilized in the apparatus 10. That is, it may be desirable to use less, but longer, capacitive ground structures 130 instead of the four structures 130 illustrated in
Referring to
In one embodiment, the circular diameter of the antenna portion may be 8.5 inches, the width of the co-planar waveguide 106 may be 500 mils (i.e., 0.5 inches), the gap between the ground pad 110 and the co-planar waveguide 106 is 80 mils (i.e., 0.08 inches), and the gap between the ground pad 110 and the antenna portion is 100 mils (i.e., 0.1 inches). In the illustrated embodiment, the printed circuit board 102 may have a height of 10.5 inches. In one or more embodiments, the antenna output 108 may include an RF connector, such as e.g., an SMA (SubMiniature version A) connector, BNC (Bayonet Neill—Concelman) connector, an F connector, and the like.
The disclosed antenna apparatus 10 is different from a traditional antenna in that it comprises the co-planar waveguide (CPWG) 106 and uses the printed circuit board's 102 ground pad 110 and the metal reflector to improve efficiency and peak gain in comparison to a traditional antenna. That is, the disclosed antenna apparatus 10 uses hybrid grounding reflectors including a ground pad and metal reflector (e.g., a metal ground plane such as vehicle's roof in a mobile system), to achieve better antenna efficiency and peak gain than the traditional antenna (which may be used in a wireless communication application with only a coplanar waveguide or micro strip ground pad as a reflector).
In use, the peak gain of the disclosed antenna apparatus 10 is approximately 1 dBi at 250 MHz. In one embodiment, the gain linearly increases to 4 dBi up to 600 MHz, and is greater than 4 dBi at frequencies between 600 MHz and 1220 MHz (1.2 GHz).
In one embodiment, the one or more connection mechanisms 244, 246, 248, 250 may be magnetic connection mechanisms configured to magnetically couple the apparatus 210 to the reflector 404. In one embodiment, the one or more connection mechanisms 244, 246, 248, 250 are held within or integral with the one or more extensions 214, 216, 218, 220 illustrated in
In one embodiment, an optional second antenna 406 may be included to detect frequencies below 250 MHZ, which may be required in certain geographical areas. If the second antenna 406 is used, the outputs of the disclosed antenna apparatus 10, 210 and the second antenna 406 are connected via cabling 414, 412, respectively, to inputs of a diplex filter 408. The output of the diplex filter 408 is connected to an input of a leakage detector 410 via cabling 416. If the system 400 only includes the antenna apparatus 10, 210 disclosed herein, then the output of the antenna apparatus 10, 210 may be directly coupled to the input of the leakage detector 410.
In one embodiment, the leakage detector 410 is mounted within the vehicle 402 using a vehicle mobile mount (not shown). In one embodiment, the leakage detector 410 may be a leakage detector from the line of Seeker™ leakage detectors manufactured and sold by VIAVI SOLUTIONS INC. In one embodiment, the leakage detector 410 may be GPS-capable (such as e.g., the Seeker™ GPS leakage detector) or coupled through a port provided for this purpose to a commercially available GPS instrument, such as one of the Garmin® or TomTom® GPS instruments capable of outputting GPS data in a standard format acceptable by the leakage detector 410.
In one embodiment, the leakage detector 410 is designed to detect the presence of the smallest amounts of signal leakage out of the HFC plant. In one embodiment, the leakage detector 410 may be able to “look” for these signals over the entire “downstream” bandwidth of the HFC network. Therefore, the system 400 needs an antenna system that makes the receiver in the leakage detector 410 optimally sensitive to these signals over a very wide range of frequencies. The antenna apparatus 10, 210 disclosed herein is designed to cover the bandwidth of 250 MHz to 1220 MHz. In the illustrated embodiment, the system 400 includes a second antenna 406, which may be a ¼ wave monopole antenna that may allow the system 400 to monitor a particular frequency in the band between 130 MHz to 150 MHz. In this way, the system 400 may have nearly continuous coverage in terms of frequency over the entire possible monitoring range, allowing the system 400 to detect all possible vulnerabilities of the HFC system both in terms of signal ingress from the outside and signal leakage from the HFC network. It should be appreciated that for many international applications, e.g., in environments where some regulations do not exist, the additional single frequency antenna 406 may not be needed at all.
The antenna apparatus 10, and in particular the matching structure 120 comprising one or more capacitive ground structures 130 disclosed herein, provides numerous advantages over the current state of the art. For example, the disclosed matching structure 120 comprising one or more capacitive ground structures 130 provides a much simpler matching method than a traditional LC (inductor-capacitor) wideband matching circuit. Moreover, the disclosed antenna apparatus 10 uses one antenna instead of two or more antennas (and a diplexer) to cover the desired frequency range of 250 MHz to 1220 MHz. As such, the overall apparatus 10 is much simpler to implement and less costly than an apparatus requiring two or more antennas to cover the desired frequency range of 250 MHz to 1220 MHz.
In addition, as shown in
It should be appreciated that without the disclosed antenna apparatus 10, 210, the mobile leakage detection system's coverage would be limited to much smaller frequency bands or even single frequencies; this is undesirable as it would result in many large coverage gaps, allowing for interference to exist but not be detected until it has reached or exceeded a harmful level. Experience and follow-up investigations into HFC interference issues have revealed that when diagnosed with a wideband antenna and a receiver capable of working with them and its frequency range (such as the apparatus 10, 210 and system 400 disclosed herein), the interference source(s) can be located and fixed in an efficient manner. Without the advantages of the disclosed principles, long and expensive troubleshooting sessions may occur and potential litigation may be needed to resolve disputes over the interference and its effects.
It should be appreciated that the disclosed antenna apparatus 10, 210 can be used in a non-mobile (i.e., static mount) system if desired. All that is required is that the capacitive ground structures 130 of the matching structure 120 be mounted to a suitable metal structure (e.g., a metal plate, pole or similar device) such that they are positioned slightly above the structure to create a capacitance for the antenna matching discussed herein.
While various embodiments have been described above, it should be understood that they have been presented by way of example and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail can be made therein without departing from the spirit and scope. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement alternative embodiments. For example, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.
In addition, it should be understood that any figures which highlight the functionality and advantages are presented for example purposes only. The disclosed methodology and system are each sufficiently flexible and configurable such that they may be utilized in ways other than that shown.
Although the term “at least one” may often be used in the specification, claims and drawings, the terms “a”, “an”, “the”, “said”, etc. also signify “at least one” or “the at least one” in the specification, claims and drawings.
Finally, it is the applicant's intent that only claims that include the express language “means for” or “step for” be interpreted under 35 U.S.C. 112(f). Claims that do not expressly include the phrase “means for” or “step for” are not to be interpreted under 35 U.S.C. 112(f).
This application is a Continuation Application of U.S. application Ser. No. 16/451,849, filed Jun. 25, 2019, the entire disclosure of which has been incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16451849 | Jun 2019 | US |
| Child | 17929928 | US |
