Defected ground structure coplanar with radio frequency component

A microwave or radio frequency (RF) device includes a substrate including an electrically insulating material. The substrate has a first surface and a second surface parallel to the first surface. The device further includes a RF component disposed over the first surface of the substrate. The device also includes a conductive layer disposed over the second surface of the substrate, the conductive layer forming a ground plane electrically insulated from the RF component. The device further includes a defected ground structure disposed on a surface of the substrate that is coplanar with the first surface, where the defected ground structure is electrically connected to the conductive layer, and where the defected ground structure includes a plurality of laterally extending members adjacent to the RF component and extending laterally in relation to the RF component.

BACKGROUND

Microwave and radio-frequency (RF) circuits can include components such as filters that can filter an input signal to generate a filtered output signals. The filters can include, for example, band-pass filters, high-pass filters, low-pass filters etc.

SUMMARY

In an embodiment, a RF device includes a substrate having a first surface and a second surface parallel to the first surface, the substrate including an electrically insulating material. The device further includes a RF component disposed over the first surface of the substrate. The device also includes a conductive layer disposed over the second surface of the substrate, the conductive layer forming a ground plane electrically insulated from the RF component. The device further includes a defected ground structure disposed on a surface of the substrate that is coplanar with the first surface, where the defected ground structure is electrically connected to the conductive layer, and where the defected ground structure includes a plurality of laterally extending members adjacent to the RF component and extending laterally in relation to the RF component.

In some embodiments, two adjacent members of the plurality of laterally extending members define a gap having a dimension in a direction that is parallel to a longitudinal axis of the RF component. In some embodiments, the plurality of laterally extending members includes at first laterally extending member that is disposed on a first side of the RF component, and a second laterally extending member that is disposed on a second side, opposite to the first side, of the RF component. In some embodiments, each of the plurality of laterally extending members has a longitudinal axis that is perpendicular to a longitudinal axis of the RF component. In some embodiments, each of the plurality of laterally extending members has a longitudinal axis that is not perpendicular to a longitudinal axis of the RF component.

In some embodiments, a shape of the defected ground structure is symmetric about a longitudinal axis of the RF component. In some embodiments, the plurality of laterally extending members are unevenly spaced. In some embodiments, at least one of the plurality of laterally extending members has a non-linear shape. In some embodiments, at least one of the plurality of laterally extending members has a fan shape. In some embodiments, at least one of the plurality of laterally extending members has a T shape. In some embodiments, the defected ground structure defines at least one loop formed by connecting at least two of the plurality of laterally extending members (e.g., with or using at least one conductive area, and/or at least one interconnecting member), the at least one loop extending around an exposed area of the first surface of the substrate. In some embodiments, the plurality of laterally extending members have non-uniform width measured in a direction that is parallel to a direction of a longitudinal axis of the RF component.

In some embodiments, the RF component includes an input terminal and an output terminal, wherein the plurality of laterally extending members are positioned adjacent a portion of the RF component between the input terminal and the output terminal. In some embodiments, a length of the plurality of laterally extending members measured in a dimension normal to a longitudinal axis of, and coplanar with, the RF component, is a function of a resonant frequency of the defected ground structure.

In some embodiments, the resonant frequency of the defected ground structure is greater than a cut-off frequency of the RF component, wherein the RF component is a low-pass filter. In some embodiments, the device further includes a band-pass filter disposed over the first surface of the substrate and coupled with the RF component, wherein the resonant frequency of the defected ground structure is greater than a highest pass-band frequency of the band-pass filter.

In some embodiments, the resonant frequency of the defected ground structure has a value in a range of 1 GHz to 300 GHz. In some embodiments, the device further includes a conductive cover disposed over the first surface of the substrate, the conductive cover electrically coupled with the defected ground structure, wherein the conductive cover covers the RF component. In some embodiments, the defected ground structure includes a conductive region extending in a direction parallel to a longitudinal axis of the RF component, wherein the conductive region is electrically coupled with a conductive cover that covers the RF component. In some embodiments, the defected ground structure includes vias for attaching a conductive cover that covers the RF component, the vias providing an electrical connection between the defected ground structure, the conductive cover, and the conductive layer.

DETAILED DESCRIPTION

The present disclosure describes devices and techniques for signal processing using microwave or RF devices (collectively referred to herein as “RF devices”). The RF devices can include a substrate having at least one ground plane and a signal terminal. One or more RF circuits can be formed on the substrate, where the RF circuits can include components such as filters, amplifiers, resonators, phase shifters, etc.

In some instances, the RF devices can include filters such as a band-pass filter, which can include, provide and/or define a pass-band in the frequency spectrum. The band-pass filter can attenuate frequency components of an input signal that lie outside of the pass-band. However, the frequency response of the band-pass filter can have repeated pass-bands at frequencies higher than the desired pass-band. Such high frequency pass-bands can be referred to as harmonics, and can undesirably introduce high frequency components of the input signal into the output signal. One approach to mitigating or suppressing the effect of harmonics in the pass-band frequency response is to cascade a low-pass filter with the band-pass filter (e.g., to form a combined band-pass and low-pass filter), where the cut-off frequency of the low-pass filter can be positioned below the frequency of the harmonics. However, the suppression by the low-pass filter is often inadequate. One approach to improving the suppression offered by the low-pass filter is to make the frequency roll-off of the low pass filter steeper. This can be achieved, for example, by adding additional resonators, or using a slow wave structure. However, these approaches can result in an increase in the size of the filter (and in turn the RF device), which is undesirable.

One solution, discussed in relation to the embodiments disclosed herein, to improving the suppression of harmonics is to utilize a defected ground structure (DGS) that is coplanar with an RF component, such as, for example, a filter. The DGS is positioned in the same plane as the RF component, and can include a plurality of laterally extending members that are positioned adjacent to the RF component. The DGS can be electrically connected to a ground plane positioned on a separate surface of a substrate on which the RF component and the DGS are disposed. The DGS can form a ground that has resonant characteristics. The resonant frequency of the DGS can be selected such that the undesirable harmonics are suppressed. The DGS (coplanar with the RF component) can be different from embodiments where a DGS is formed within a ground plane that is positioned on a separate surface of the substrate that does not include the RF component. Such a ground plane is typically a solid sheet of metal (with vias), and a DGS in the ground plane can be a negative space (or voids) in the metal sheet, which produces an effect on the signal of the RF component. In contrast, the coplanar DGS discussed in the embodiments herein is a positive space (e.g., conductive material extended from or added) to a ground structure that is brought to (or extended to) the same layer as the signal path, making the DGS coplanar with the RF component. The coplanar DGS also affects the signal in the RF component. However, the effect is not produced by voids, but produced by laterally extending resonant structures of conductive material on the same layer as the RF component.

In some embodiments, a set of vias can connect the DGS to the ground plane through the substrate. The laterally extending members extend laterally from the set of vias (e.g., towards the RF component and electrically insulated from the RF component) but are physically isolated from the RF component. An effective length of each laterally extending member can be a function of a frequency. For example, the effective length can be a quarter wavelength or half wavelength of the frequency of the harmonics that are to be suppressed. The effect on the signal created by the laterally extending member can be a function of frequency. In some embodiments, the effective length of the laterally extending member can be expressed in terms of electrical length, such as the that mentioned above, in the form of a function of the wavelength. In some embodiments, the effective length can be expressed in the form of distance units, such as mils (thousands of an inch), microns, etc. In some embodiments, the effective length can be a function of the frequency of the harmonics that are to be suppressed and the materials used to form the substrate and the RF component.

In some embodiments, DGS can include the laterally extending members that are positioned on one side or each side of the RF component. In some embodiments, the DGS can include laterally extending members of various shapes, such as rectangular, T-shaped, looped, fan-shaped. In some embodiments, the DGS can include laterally extending members that have non-uniform dimensions or spacing. The shape and sizes of the laterally extending members can be selected based on the desired resonant frequency response.

FIG. 1shows an isometric view of an example RF device100. The RF device100includes a substrate102and a cover104disposed on the substrate102. The substrate102can include a first surface106and an opposite second surface (not shown) that faces in a direction opposite to the direction in which the first surface106faces. In some embodiments, the second surface can be in a plane that is parallel to a plane of the first surface106. The substrate102also includes side surfaces108that extend between the first surface106and the opposite second surface. One or more RF components can be formed over the first surface106of the substrate102. A ground plane can be formed on the second surface of the substrate102, which is for instance not coplanar with the one or more RF components. The ground plane can be a metal or a conductive layer that covers the second surface of the substrate102(shown inFIGS. 12-14). The substrate102can be formed using non-conductive materials such as, for example, ceramics (e.g., alumina, aluminum nitride, and beryllium oxide), plastic, glass, semiconductors (e.g., gallium arsenide (GaAs), indium phosphate (InP), and silicon), and other non-conductive materials.

The cover104is disposed on and affixed to the substrate102. The cover104is conductive, and can be formed using materials such as, for example, copper, aluminum, silver, gold, etc. At least a portion of the cover104can also cover one or more side surfaces108of the substrate102. For example, the cover104can include a cover plate110and two side cover plates112. The two side cover plates112are coupled to two opposite sides of the cover plate110of the cover104. Two side surfaces108of the substrate102can include a conductive coating with which the two side cover plates112can make contact. The conductive coating on the two side surfaces108of the substrate102can be electrically connected to the ground plane on the second surface of the substrate102. By having the two side cover plates112be in contact with the conductive coating on the side surfaces108, the cover104is electrically connected to ground. Portions of the two side cover plates112can be attached to the conductive coating on the side surfaces108by way of screws, adhesive, epoxy, solder and the like. In some instances, the first surface106can include vias with which at least portions of the two side cover plates112can be coupled. For example, one or more vias can be positioned along the peripheries of first surface106of the substrate102. The vias can include a conductive coating which is electrically connected to the ground plane positioned on the second surface of the substrate102. The vias can include openings or slots (with conductive coatings) in which portions of the two side cover plates112can be inserted. At least a portion of each of the two side cover plates112can be positioned over or inserted into the vias on the substrate102. The two side cover plates112can be attached to the vias by way of screws, adhesive, epoxy, solder and the like.

One or more RF components can be disposed on or within the substrate102. For example, one or more RF components can be formed on the first surface106of the substrate102.FIG. 2shows one example RF component200disposed on the first surface106of the substrate102of the RF device100shown inFIG. 1. The RF component200shown is a low-pass filter, however any other RF component, such as a high-pass filer, a band-pass filter, an amplifier, a transmission line, etc. can be included. A DGS202is formed on the first surface106of the substrate102. The DGS202is coplanar with the RF component200. That is, the surface on which the DGS202is formed is coplanar with the surface on which the RF component200is formed. In some embodiments, the RF component200can be a distributed elements RF component. Distributed elements RF components can utilize pattered geometries of metal to produce a desired effect on an input signal provided to the RF components. This is in contrast to lumped elements RF components, which utilize discrete components, such as capacitors and inductors. In some embodiments, the RF device100can include a combination of distributed elements RF components and lumped elements RF components.

A first conductive area204and a second conductive area206are formed on the first surface106of the substrate102. The first conductive area204and the second conductive area206are electrically coupled to a ground plane formed on the second surface of the substrate102. In the embodiment shown inFIG. 2, the first conductive area204and the second conductive area206are connected to the ground plane by vias. Alternatively, the first conductive area204and the second conductive area206can be connected to the ground plane on the second surface of the substrate102by conductive coating on the side surfaces108of the substrate that make contact with the first and the second conductive areas204and206on the first surface and also make contact with the ground plane on the second surface of the substrate102. As shown inFIG. 2, the first conductive area includes a first set of vias208and the second conductive area includes a second set of vias210. The first set of vias208form a conductive path between the first conductive area204and the ground plane, while the second set of vias210form a conductive path between the second conductive area206and the ground plane on the second surface of the substrate102.

The two side cover plates112of the cover104can be attached to or make contact with the first conductive area204and the second conductive area206. In some embodiments, the two side cover plates112can include protrusions that can be inserted into the first set of vias208and the second set of vias210. In this manner, the cover104is electrically connected to the ground plane on the second surface of the substrate102.

The DGS202is also electrically connected to the ground plane on the second surface of the substrate102through the vias or the conductive coatings on the side surfaces108of the substrate102. The DGS202includes a plurality of laterally extending members212that extend laterally in relation to the RF component200. In particular, the laterally extending members212can be positioned such that two adjacent laterally extending members are separated by a gap. For example, two adjacent laterally extending members212A and212B are separated by a gap214that has a dimension in a direction that is parallel to a longitudinal axis216of the RF component200.

The DGS202can include laterally extending members212that are disposed on either side of the RF component200. For example, the DGS202can include a first laterally extending member212A that is positioned on one side of the RF component200and a second laterally extending member212C that is positioned on the opposite side of the RF component200. Specifically, the first laterally extending member212A is positioned on the side of the RF component200on which the first set of vias208are positioned and the second laterally extending member212C is positioned on the side of the RF component200on which the second set of vias210are positioned. In some instances, being positioned on either side of the RF component200can refer to being positioned on either side of the longitudinal axis216of the RF component200. The DGS202can include a plurality of laterally extending members212on either side of the RF component200.FIG. 2shows the DGS202including ten laterally extending members212on either side of the RF component200. However, the number of laterally extending members212on either side of the RF component200can be different from that shown inFIG. 2. As an example, the DGS202can include at least two laterally extending members212on either side of the RF component200, where any two adjacent laterally extending members212on one side of the RF component200are separated by a gap, such as, for example, the gap214, which has a dimension in a direction that is parallel to the longitudinal axis216of the RF component200.

Each of the plurality of laterally extending members212has a longitudinal axis218that is perpendicular to the longitudinal axis216of the RF component200. In some instances, a subset of the laterally extending members212can have their respective longitudinal axes that are not perpendicular to the longitudinal axis216of the RF component200. At least one example of laterally extending members212having longitudinal axes that are not perpendicular to the longitudinal axis216of the RF component is discussed below in relation toFIG. 6.

The plurality of laterally extending members212are positioned adjacent to a portion of the RF component200between an input terminal and an output terminal of the RF component200. For example, the RF component200includes an input terminal220positioned on one end of the RF component200and an output terminal222positioned on an opposite end of the RF component200along the longitudinal axis of the RF component200. The input terminal220and the output terminal222can be connected to one or more RF components formed on the substrate102or formed on a different substrate. The RF component200includes a portion224that is positioned between the input terminal220and the output terminal222. The DGS202is positioned adjacent to the portion224of the RF component200. In some embodiment, the DGS202does not extend beyond the input terminal220and the output terminal222along the longitudinal axis216of the RF component200. However, in some other embodiments, a portion of the DGS202may extend beyond the input terminal220or the output terminal222along the longitudinal axis216of the RF component200(for example, as shown inFIG. 15). The DGS202can be spaced apart from the RF component200. For example, the DGS202can be separated from the RF component200by a distance D on either side of the RF component200. In some embodiments, the value of D can be between 5 mils and 100 mils. In some embodiments, the distance of separation of the DGS202on one side of the RF component200can be equal to the distance of separation of the DGS202on the other side of the RF component200. However, in some other embodiments, such as where the DGS is asymmetrical about the longitudinal axis216of the RF component200, these distances of separation can be unequal.

The DGS202is electrically connected to the first conductive area204and the second conductive area206, which extend on the first surface106of the substrate102in a direction that is parallel to the longitudinal axis216of the RF component200. For example, the laterally extending member212A is electrically connected to an edge226of the first conductive area204. Similarly, the second laterally extending member212C is electrically connected to an edge228of the second conductive area206. As mentioned above, the first and second conductive areas204and206are electrically connected to the conductive cover104, which covers the RF component200, and are electrically connected to the ground plane on the second surface of the substrate102. In some instances, where the first and the second conductive areas204and206are not formed, the laterally extending members212may be electrically connected to the first set of vias208and the second set of vias210, or can extend to the edges of the first surface106where they are electrically connected to the conductive coating on the side surfaces108of the substrate102. In this manner, the DGS202and the cover104are electrically connected to the ground plane.

A laterally extending member212can have a length Lm measured along the longitudinal axis218of the laterally extending member212, and a width Wm measured in a direction perpendicular to the direction of the longitudinal axis218of the laterally extending member212. In some embodiments, the length Lm can have values between 10 mils and 1200 mils, and width Wm can have values between 2 mils and 48 mils. In some embodiments, the values of Lm and Wm can be expressed in electrical length, i.e., in terms of a function of a wavelength and permittivity of the material used to form the substrate102. In some embodiments, the 50 ohm laterally extending member212at an example frequency of 20 GHz and permittivity values of the substrate in the range of 2 to 200 can have a length Lm with values in the range of 10 mils to 200 mils. In some embodiments, the 50 ohm laterally extending member212at an example frequency of 2 GHz and permittivity values of the substrate in the range of 2 to 200 can have a length Lm with values in the range of 100 mils to 1500 mils. In the example shown inFIG. 2, the lengths Lm of all laterally extending members212are equal, and the widths Wm of all laterally extending members212are equal. However, the laterally extending members212can have non-uniform lengths Lm or non-uniform widths Wm. In some embodiments, the DGS202can be symmetrical about the longitudinal axis216of the RF component200. That is, the number of laterally extending members212on one side of the RF component200is equal to the laterally extending members212on the other side of the RF component200. Further, the dimensions (length Lm and width Wm) of a laterally extending member212on one side of the RF component200are the same as the corresponding dimensions of the corresponding laterally extending member212on the other side of the RF component200. In some instances, the DGS202can be asymmetrical about the longitudinal axis216of the RF component200. That is, at least one aspect of: a number of laterally extending members212, a length of an laterally extending member212, a width of an laterally extending member212, a gap between adjacent laterally extending members212, or a distance of separation between an laterally extending member212and the RF component200on one side of the RF component200can be different from the corresponding aspect on the other side of the RF component200.

As mentioned above, the dimensions of the laterally extending members212can be selected based on a desired resonant frequency of the DGS202. The resonant frequency of the DGS202, in turn, can be selected based in part on the frequencies identified to be suppressed.FIGS. 3 and 4show the RF component200shown inFIG. 2without the DGS202and the corresponding frequency response curves400. The RF component200shown inFIG. 3is a low-pass filter, andFIG. 4shows an insertion loss curve402and a return loss curve404corresponding to the simulation of the RF component200shown inFIG. 4. The cut-off frequency of the RF component200is indicated by “Fc”. The RF component200exhibits harmonics and spurious modes at frequencies higher than the cut-off frequency Fc. For example, “Fr” indicates the frequency at which harmonics and spurious modes manifest in the response characteristics of the RF component200. In the example shown inFIG. 4, Fc is approximately 23 GHz, and Fr is approximately 36 GHz. The DGS202can be designed to suppress or move to higher frequencies the harmonics and spurious modes exhibited by the RF component200. For example, the dimensions of the laterally extending members212can be selected such that the resulting resonant frequency of the DGS202corresponds to the frequency Fr. As an example, referring to the DGS202shown inFIG. 2, the length Lm of the laterally extending member212can be selected to be equal to λ/4 or 2λ/3, where λ is the wavelength corresponding to the frequency Fr.

FIG. 5shows frequency response curves500for the RF component200when used in combination with the coplanar DGS202shown inFIG. 2. In particular, the frequency response curves500include the insertion loss curve502and the return loss curve504. The frequency response curves500have been generated based on a cover, such as the cover104shown inFIG. 1, positioned over the first surface106of the substrate102. As shown inFIG. 5, the inclusion of the coplanar DGS202results in a favorable change in the response curves of the RF component200. In particular, the harmonics and spurious modes that appeared at frequency Fr, are instead pushed to a higher frequency F′r. For example, the DGS202causes the harmonics and spurious modes to appear at a relatively higher frequency of approximately 40 GHz. The DGS202can provide a ground that has resonant characteristics, the resonance frequency of which can be selected to align with the frequency at which the harmonics and spurious modes appear. The resulting overall frequency response of the RF component200utilizing the coplanar DGS202suppresses or pushes the harmonics and spurious modes to higher frequencies. In the example shown inFIG. 5, the harmonics and spurious modes are pushed to a frequency F′r, which is at about 40 GHz. The resonant frequency of the DGS202can be set between a range of 1 GHz to 300 GHz.

FIG. 6shows a top view of a substrate of an RF device600including a second example coplanar DGS602. The RF component200shown inFIG. 6is the same RF component discussed above in relation toFIG. 2. The RF device600further includes a second example DGS602that is coplanar with the RF component200. The second example DGS602is similar in many respects to the first example DGS202discussed above in relation toFIGS. 2-6. However, unlike the laterally extending members212of the first example DGS202, whose longitudinal axes218are perpendicular to the longitudinal axis216of the RF component, the laterally extending members612of the second example DGS602have longitudinal axes618that form a non-perpendicular angle β with the longitudinal axis216of the RF component200. In some embodiments, the angle β can have a value between 10 degrees and 89 degrees. By placing the laterally extending members612at an angle that is not perpendicular with respect to the longitudinal axis216of the RF component200allows the laterally extending members612to be longer with respect to the length Lm of the laterally extending members212shown inFIG. 2. The length Lm of the laterally extending members612can be determined based on the desired resonant frequency. If the space between the RF component200and the first and second conductive areas204and206is inadequate to accommodate the laterally extending members612in an orientation that is perpendicular to the longitudinal axis216of the RF component200, then the laterally extending members612can be oriented in with an appropriate angle β. This can be particularly beneficial in instances where the overall width of the substrate102cannot be changed due to packaging restrictions. In some embodiments, at least a portion of the DGS602may extend beyond the input terminal220or the output terminal222along the longitudinal axis216of the RF component200. Aspects such as symmetry of the DGS602, width of laterally extending members612, and spacing of the laterally extending members612, can be similar to the respective aspects of the DGS202discussed above in relation toFIGS. 2-5.

FIG. 7shows frequency response curves700for the RF component200when used in combination with the coplanar second example DGS602shown inFIG. 6. In particular, the frequency response curves700include the insertion loss curve702and the return loss curve704. The frequency response curves700have been generated based on a cover, such as the cover104shown inFIG. 1, positioned over the first surface106of the substrate102. As shown inFIG. 7, the inclusion of the coplanar second example DGS602results in a favorable change in the response curves of the RF component200. In particular, the harmonics and spurious modes that appeared at frequency Fr, are instead pushed to a higher frequency F′r. For example, the second example DGS602causes the harmonics and spurious modes to appear at a relatively higher frequency of approximately 38 GHz.

FIG. 8shows a top view of a substrate of an RF device800including a third example coplanar DGS802. The RF component200shown inFIG. 8is the same RF component discussed above in relation toFIG. 2. The RF device800further includes the third example DGS802that is coplanar with the RF component200. The third example DGS802is similar in many respects to the first example DGS202discussed above in relation toFIGS. 2-6. However, unlike the laterally extending members212of the first example DGS202, which have a linear shape, the laterally extending members812of the third example DGS802have a non-linear shape. In particular, the laterally extending members812of the third example DGS802are ‘T’ shaped. The third example DGS802includes three ‘T’ shaped laterally extending members812on each of the two sides of the longitudinal axis216of the RF component200. However, in some other embodiments, the number of laterally extending members812can be different from that shown inFIG. 8. Each laterally extending member812can include a first segment852and a second segment862. The first segment852extends between the first conductive area204and the second segment862. A portion between the ends of the second segment862is connected to the first segment852. A longitudinal axis of the first segment852can form an angle α with a longitudinal axis of the second segment862. In the embodiment shown inFIG. 8, the angle α is equal to 90 degrees. However, in some embodiments, the angle α can be an acute or an obtuse angle. The longitudinal axis818of the first segment852is perpendicular to the longitudinal axis216of the RF component200. In some embodiments, the longitudinal axis818can form a non-perpendicular angle with the longitudinal axis216of the RF component200.

The length Lm1of the first segment852is greater than the length Lm2of the second segment862. In some embodiments, the length Lm1of the first segment852can be equal to, or greater than, the length Lm2of the second segment862. The width Wm1of the first segment852is equal to the width Wm2of the second segment862. However, in some embodiments, the width Wm1can be greater than or less than the width Wm2. In some embodiments, the dimensions of the first segment852and the second segment862can be determined based on the desired resonant frequency of the third example DGS802. The ‘T’ shape of the laterally extending member812has an effective length Leff that is greater than the length Lm1of the first segment852. In some instances, the Leff can be a sum of the lengths Lm1and Lm2of the first and the second segments852and862. In some other instances, the effective length Leff of the laterally extending member812can be a less than the sum of the lengths Lm1and Lm2. Generally, the effective length Leff of the laterally extending member812is a function of the lengths Lm1and Lm1of the first and second segments852and862, respectively. In some embodiments, the Lm1can have values between 20 mils and 60 mils, Lm2can have values between 20 mils and 60 mils, Wm1can have values between 2 mils and 12 mils, and Wm2can have values between 2 mils and 12 mils. These values can be based on a signal frequency between 2 GHz and 20 GHz and permittivity (of the substrate102) between 2 and 200. In some embodiments, the angle α can have values between 60 degrees and 120 degrees. Aspects such as symmetry of the DGS802, width of laterally extending members812, and spacing of the laterally extending members812can be similar to the respective aspects of the DGS202discussed above in relation toFIGS. 2-5.

FIG. 9shows frequency response curves900for the RF component200when used in combination with the coplanar third example DGS802shown inFIG. 8. In particular, the frequency response curves900include the insertion loss curve902and the return loss curve904. The frequency response curves900have been generated based on a cover, such as the cover104shown inFIG. 1, positioned over the first surface106of the substrate102. As shown inFIG. 9, the inclusion of the coplanar third example DGS802results in a favorable change in the response curves of the RF component200. In particular, the harmonics and spurious modes that appeared at frequency Fr, are instead pushed to a higher frequency F′r. For example, the third example DGS602causes the harmonics and spurious modes to appear at a relatively higher frequency of approximately 40 GHz.

FIG. 10shows a top view of a substrate of an RF device1000including a fourth example coplanar DGS1002. The RF component200shown inFIG. 10is the same RF component discussed above in relation toFIG. 2. The RF device1000further includes the fourth example DGS1002that is coplanar with the RF component200. The fourth example DGS1002is similar in many respects to the first example DGS202discussed above in relation toFIGS. 2-6. However, unlike the laterally extending members212of the first example DGS202, which have a linear shape, the laterally extending members1012of the fourth example DGS1002have a non-linear shape. In particular, the laterally extending members1012of the fourth example DGS1002are fan-shaped. The fourth example DGS1002includes three fan-shaped laterally extending members1012on each of the two sides of the longitudinal axis216of the RF component200. However, in some other embodiments, the number of laterally extending members1012can be different from that shown inFIG. 10. A longitudinal axis1018of the laterally extending members1012is perpendicular to the longitudinal axis216of the RF component200. However, in some other embodiments, the longitudinal axis1018of the laterally extending members1012can form a non-perpendicular angle with the longitudinal axis216of the RF component200. The laterally extending member1012can have a length Lm and a width Wm. The dimensions of the laterally extending members1012can be a function of the desired resonant frequency. The frequency response of the RF component200can be similar to the frequency response of shown inFIGS. 5, 7, and 9. That is, the fourth DGS1002can suppress the harmonics and the spurious mode or push them to higher frequencies. Aspects such as symmetry of the fourth DGS1002, width of laterally extending members1012, and spacing of the laterally extending members1012can be similar to the respective aspects of the DGS202discussed above in relation toFIGS. 2-5.

FIG. 11shows a top view of a substrate of an RF device1100including a fifth example coplanar DGS1102. The RF component200shown inFIG. 11is the same RF component discussed above in relation toFIG. 2. The RF device1100further includes the fifth example DGS1102that is coplanar with the RF component200. The fifth example DGS1102has a looped shape. In particular, the fifth example DGS1102includes two laterally extending members1112A and1112B, one end of each of which is connected to the first conductive area204. The two laterally extending members1112A and1112B may be interconnected to form the looped shape. For instance, the other end of each of the two laterally extending members1112A and1112B may be connected with an interconnecting member1112C, which can be formed of the same material as the two laterally extending members1112A and1112B. The two laterally extending members1112A and1112B in combination with the interconnecting member1112C and the first conductive area204, can define a loop that extends around an exposed area1106of the first surface106of the substrate102. A similar loop can be formed on the other side of the longitudinal axis216of the RF component200. The two laterally extending members1112A and1112B can have a length Lm and a width Wm. The longitudinal axes1118of the two laterally extending members1112A and1112B can extend laterally relative to (e.g., be perpendicular to, or extend at an angle relative to) the longitudinal axis216of the RF component200. In some other embodiments, the longitudinal axes1118can be at a non-perpendicular angle with the longitudinal axis216of the RF component200. The overall width W1of the looped shaped fifth DGS1102along with the dimensions of the laterally extending members1112A and1112B, and the dimensions of the interconnecting member1112C can be a function of the desired resonant frequency of the fifth DGS1102. In some embodiments, the width WI can have a value between 8 mils and 300 mils. The frequency response of the RF component200can be similar to the frequency response of shown inFIGS. 5, 7, and 9. That is, the fifth DGS1102can suppress the harmonics and the spurious mode or push them to higher frequencies. WhileFIG. 11shows a single loop formed on each side of the longitudinal axis216of the RF component200, in some embodiments, the DGS1102can include more than one loop on each side. In some embodiments, the length Lm can have values between 10 mils and 1200 mils, and width Wm can have values between 10 mils and 1200 mils. In some embodiments, the values of Lm and Wm can be expressed in electrical length, i.e., in terms of a function of a wavelength and permittivity of the material used to form the substrate102. In some embodiments, the 50 ohm laterally extending member1112at an example frequency of 20 GHz and permittivity values of the substrate in the range of 2 to 200 can have a length Lm with values in the range of 10 mils to 200 mils. In some embodiments, the 50 ohm laterally extending member1112at an example frequency of 2 GHz and permittivity values of the substrate in the range of 2 to 200 can have a length Lm with values in the range of 100 mils to 1500 mils. Aspects such as symmetry of the fifth DGS1102, width of laterally extending members1112, and spacing of the laterally extending members1112can be similar to the respective aspects of the DGS202discussed above in relation toFIGS. 2-5.

FIG. 12shows a cross-sectional view of the RF device100shown inFIG. 1. In particular, the cross-sectional view shows the substrate102and the RF component200disposed on the first surface106of the substrate102. A cover is not shown for simplicity. The RF device100also includes a DGS202that is also disposed on the first surface106on which the RF component200is disposed. While DGS202corresponds to the DGS202shown inFIG. 2, any of the other DGSs discussed herein can also be disposed on the first surface106. That is, the DGS202is coplanar with the RF component200. The substrate102includes a second surface160opposite the first surface106. A conductive layer162is disposed over the second surface160of the substrate102, and forms a ground plane that is electrically insulated from the RF component200by the substrate102. While not shown inFIG. 12, the DGS202is electrically connected to the conductive layer162by way of vias (e.g.,208and210,FIG. 2) or conductive coatings on the side surfaces (e.g.,108,FIG. 1).

FIG. 13shows a cross-sectional view of an RF device1300that includes embedded RF components and coplanar DGS. In particular, the RF device1300includes an RF component200that is embedded in a substrate102. The RF component200is disposed on a first embedded surface1306of the substrate102. The RF device1300also includes a DGS202similar to those discussed above. The DGS202is also embedded in the substrate102and is disposed on a second embedded surface1308of the substrate102. Thus, both the RF component200and the DGS202are disposed within the substrate102between the first surface106and the second surface160of the substrate102. Further, the first embedded surface1306is coplanar with the second embedded surface1308, and separated from each other by intervening material of the substrate102. The first embedded surface1306(e.g., having the RF component2000) and the second embedded surface1308(e.g., having the DGS202) may not physically extend into or overlap with each other to form a single surface. Thus, the DGS202can be coplanar with the RF component200, and be electrically insulated or isolated from the RF component200by intervening material of the substrate102. In some instances, the substrate102can be formed by combining two or more separate substrate layers. For example, a substrate layer of the same material as the substrate102shown inFIG. 12can be positioned over the substrate102shown inFIG. 12and cover the RF component200and the DGS202. The resulting RF device would have the RF component200and the DGS202embedded between the two substrate layers similar to that shown inFIG. 13. The process for forming the RD devices shown inFIGS. 12-13(andFIG. 14discussed below) can vary and can in some embodiments, be based on the material utilized for forming the substrate. In some embodiments, the substrate102can be formed sub-layer by sub-layer (e.g., by deposition techniques), or built in separate independent layers that are bonded to each other, and where the metal layers representing the coplanar DGS and the RF component can be bonded to the respective surfaces of the substrate102.

FIG. 14shows a cross-sectional view of a strip line RF device1400that includes an embedded RF component and an embedded coplanar DGS. In particular, the strip line RF device1400includes a substrate102having a first surface106and an opposite second surface160. A first conductive layer164is disposed on the first surface106and a second conductive layer162is disposed on the second surface160. The first conductive layer164and the second conductive layer162form ground planes, and are electrically connected to each other. The RF component200and the DGS202are embedded in the substrate102. The RF component200is disposed on a first embedded surface1406of the substrate102, and is electrically insulated from both the first conductive layer164and the second conductive layer162. The DGS202is disposed on a second embedded surface1408, where the first embedded surface1406and the second embedded surface1408are coplanar (e.g., similar to the features discussed above in connection withFIG. 13). Thus, the DGS202is coplanar with the RF component200. In some instances, the substrate102can be formed by combining two or more separate substrate layers. The coplanar DGS202can be implemented in other strip-line RF devices as well.

FIG. 15shows an example RF device1500including a band pass filter1550and a low pass filter200having a coplanar DGS202. While not shown inFIG. 14, the RF device1500also includes a cover, such as the cover104shown inFIG. 1, disposed over the substrate102. The band pass filter1550is disposed over the first surface106of the substrate102. The low pass filter200is coplanar with the DGS202. In some embodiments, the DGS202can extend beyond the input terminal220or the output terminal222along the longitudinal axis216of the RF component200. In some embodiments, the DGS202can be extended to be adjacent to the band pass filter1550as well. In some such embodiments, the size of the substrate102can be selected to accommodate a DGS on one or both sides of a longitudinal axis of the band pass filter1550. The resonant frequency of the DGS can be selected to be greater than both a center frequency of the band pass filter1550and the cut off frequency of the low pass filter200.

FIG. 16shows frequency response curves for the RF component200when used in combination with the coplanar fourth example DGS1002shown inFIG. 10. The harmonics and spurious modes are suppressed or pushed to a higher frequency.

FIG. 17shows a top view of a substrate of an RF device including a variation of the fifth example coplanar DGS1102shown inFIG. 11. In particular, the DGS includes more than one loop on each side of a longitudinal axis of the RF component.