Abstract: A dual function catheter handle for simultaneous movement of two control wires has a handle housing having a core with a longitudinal slot mounted in its interior. A first moveable member is provided with a proximal end mounted in the interior of the handle housing and a distal end extending outside the handle housing. The first moveable member is longitudinally moveable relative to the handle housing. A second moveable member is mounted in the longitudinal slot of the core and is longitudinally moveable relative to the core and handle housing. A rotatable member is mounted on the handle housing and has a threaded inner surface that mates with a threaded surface of the second moveable member so that rotation of the rotatable member causes longitudinal movement of the second moveable member. The first and second moveable members can simultaneously move proximally relative to the handle housing.

Abstract: A method for determining a three dimensional representation of a tubular organ, the method comprising the procedures of registering a three dimensional medical positioning system (MPS) coordinate system with a two dimensional coordinate system, acquiring a plurality of MPS points within the tubular organ, the MPS points are associated with the MPS coordinated system, each of the MPS point is acquired with a respective organ timing signal reading, acquiring at least one two dimensional image of the tubular organ, the at least one two dimensional image is associated with the two dimensional coordinate system, the at least one two dimensional image is acquired from at least one perspective, each of the at least one two dimensional image is further acquired with a respective organ timing signal reading, associated each of the MPS points with the at least one two dimensional image according to the organ timing signals thereof, determining a temporal three dimensional representation of a portion of the tubular orga

Abstract: A device for gripping a guide wire includes a body portion having an opening therethrough, and has an open position and a closed position. When the device is in the open position the guide wire may be passed through the opening. When the device is in the closed position the guide wire is gripped at more than one location thereby allowing force or torque to be applied to the guide wire. A device according to the invention may optionally, or instead, include (a) a snout to act as a guide wire director, (b) a structure, such as an opening, configured to receive an end of a guide wire package, (c) a structure for securing a body member to the device, and/or (d) a mechanism for advancing or retracting a guide wire. If the device includes one of these optional features, it need not be designed to grip a guide wire at two or more locations.

Abstract: A medical device with improved flexibility characteristics and methods of using the same. The medical device may include a proximal end, a distal end, and an intermediate region. In at least some embodiments, the column strength or flexibility of the intermediate portion is generally greater than the column strength or flexibility at the distal end.

Abstract: A vascular access catheter having a catheter shaft configured for insertion into a vein of a patient. The catheter has an exterior surface, which has a plurality of openings defined in the distal end portion of the catheter shaft, and can have respective first and second lumens. The first lumen is in fluid communication with at least one opening of the plurality of openings and is in communication with a first extension tube. The catheter has a first extension tube and a second extension tube. The first extension tube is positioned in fluid communication with the first lumen, and the second extension tube is positioned in fluid communication with the second lumen. The second extension tube is configured for high pressure CT injections, and the first extension tube is longer in length than the second extension tube.

Abstract: A system for and method of determining and compensating for the effect of a field influencing object on a field sensor, preferably a coil, that is within a navigational domain. The system includes a first and second transmitter to create signals. A signal processor is able to process the created signals. The method can include determining interference and/or a correct signal based on the two signals. Also, a shield can be provided to limit transmission of selected fields.

Abstract: A method of delivering therapy to a target site. The method includes (a) obtaining a base image of the target site, (b) injecting a dose of a mix of a therapeutic agent and a contrast agent into a first injection location at the target site via a needle passing through a catheter, (c) collecting sequential fluoroscopic images of a contrast agent dispersion cloud at the first injection location, (d) determining a contrast agent dispersion area from the sequential fluoroscopic images, (e) determining a therapeutic agent dispersion area from the contrast agent dispersion area, (f) marking the therapeutic agent dispersion area on the base image of the target site, and (g) repeating (b) through (f) until the target site is substantially covered with overlapping therapeutic agent dispersion areas corresponding to a plurality of injections at a plurality of injection locations at the target site.

Abstract: A medical instrument such as a guidewire that is designed to have controlled torque transmission along its length. Specially treated areas are placed in selected and equal areas along the entire length of the elongated shaft of the medical instrument, and are separated from one another by untreated areas. This process ensures that any torque is transmitted distally, in a smooth manner, regardless of the guidewire position, thus resulting in a substantial reduction in whipping. In one embodiment, a stainless steel guidewire is utilized, and is subjected to annealing heat treatment in selected areas. This annealing process creates a mandrel that has repeated temper properties along its length. Torque applied at one end of this mandrel is transmitted to the opposite end in an even and controlled manner, even when the mandrel is formed into a loop.

Abstract: Method for delivering a stent coupled with a catheter, to a selected position within a lumen of the body of a patient, the method includes the procedures of: selecting a single image of the lumen, among a plurality of images of an image sequence of the lumen, receiving a position input associated with the selected image and respective of the selected position, the position input is defined in a coordinate system respective of a medical positioning system (MPS), detecting the current position of the stent in the coordinate system, according to position data acquired by an MPS sensor attached to the catheter in the vicinity of the stent, superimposing on at least one maneuvering associated image of the lumen, at least one stent representation respective of the current position, and at least one marking representation respective of the position input, according to a real-time organ timing signal of an inspected organ of the body, maneuvering the catheter through the lumen, toward the selected position, according

Abstract: Catheters such as guide catheters can be configured for delivery of devices to vasculature portions such as intracranial spaces while retaining a desired level of flexibility. A catheter having an elongate shaft can include removable support means that can provide column support to the elongate shaft. The elongate shaft can include anchoring means that releasably secure the removable support means. The catheter can be deployed within a patient's vasculature, followed by deploying the removable support means.

Abstract: A medical device having a segmented construction. In at least some embodiments, a medical device including a plurality of conductive elongated members that are of such a length and are connected together in such a manner to impart a degree of MRI compatibility to the device. In some embodiments, the elongated members can include a series of solid elongate members and tubular elongate members, which construction provides one way to control at least some properties of the device, for example, stiffness, torque transmission, flexibility, shape retention, and the like. In yet some additional embodiments, at least one of the elongated members has a recess into which a protrusion of another elongated member may fit.

Abstract: Alternative designs, materials and manufacturing methods for guidewires. Some embodiments pertain to a composite guidewire having proximal and distal section, and a connector adapted and configured for permanently joining the proximal section to the distal section. In some embodiments, at least one of the sections is made of a linear-elastic nickel-titanium alloy. Several alternative guidewire tip designs including coiled safety/shaping structures are also disclosed.

Abstract: A method for planning left atrial appendage (LAA) occlusion for a patient includes obtaining acquisition data from a medical imaging system, and generating a 3D model of the left atrium of the patient. One or more left atrial anatomical landmarks are identified on the 3D model, and saved views of the 3D model are registered on an interventional system. One or more of the registered saved views are visualized with the interventional system.

Abstract: Systems and methods of increasing blood flow in a blood vessel with ultraluminal plaque. One disclosed method includes inserting an imaging guidewire into the blood vessel to the intraluminal plaque, propelling a catheter with a working head over the guidewire towards the distal end of the guidewire, scanning with the imaging guidewire to generate a cross-section image, radially positioning the catheter using a positioning element, monitoring the image to ascertain that the working head is properly positioned and operating the working head to remove the plaque. A computerized system designed, constructed and configured to perform the methods is further disclosed.

Abstract: The present invention is directed to an intracorporeal device, preferably a guidewire, and method for making the device. The guidewire of the present invention is formed, at least in part, of a composite elongate core formed, at least in part, of precipitation hardened material. The elongate core members of the present invention will have an ultimate tensile strength and modulus of elasticity greater than the same for an identically dimensioned elongate member formed from superelastic NITINOL alone.

Abstract: A guide wire (1) to assist percutaneous endovascular deployment which has zones of varying stiffness. An elongate central zone (3) of high stiffness, a proximal zone (4) of transition from high stiffness to semi-stiffness and a distal zone (5) of transition from high stiffness to being relatively flexible. The distal zone (5) has three zones, a semi stiff zone (11) adjacent the central zone, a transition zone (13) being of flexibility of from semi-stiff extending to flexible and a tip zone (15) being of high flexibility. The distal tip has a small J curve (16) to ensure that it is atraumatic in vessels and to prevent damage to the aortic heart valve. The distal zone (5) can also have a large curve to assist with anchoring the guide wire into the aortic arch.

Abstract: The present invention realizes a medical device guidance system capable of improving propulsion control characteristic.

Abstract: An insertion tool for use in inserting a guide wire into a guide wire lumen of a catheter for use in a lumen of an endoscope. The insertion tool includes a main body having a main lumen and a funnel-shaped extension connected to and disposed atop the main body. The funnel-shaped extension having a funnel lumen. The funnel lumen has a top opening and a bottom opening. The funnel lumen tapering from the top opening to the bottom opening. The bottom opening positioned and sized to communicate with the guide wire lumen of the catheter such that, when the catheter is disposed in the main lumen, the guide wire may be easily inserted into the top opening of the funnel lumen and into the guide wire lumen of the catheter.

Abstract: Medical imaging and navigation system including a processor, a display unit, a database, a medical positioning system (MPS), a two-dimensional imaging system, an inspected organ monitor interface, and a superimposing processor, the MPS including a transducer MPS sensor and a surgical tool MPS sensor, the two-dimensional imaging system including an imaging transducer, the processor being connected to the display unit, to the database, to the MPS, to the two-dimensional imaging system, to the inspected organ monitor interface, and to the superimposing processor, the inspected organ monitor interface being connected to an organ monitor, the surgical tool MPS sensor being firmly attached to a surgical tool, the transducer MPS sensor being firmly attached to the imaging transducer, the organ monitor monitoring an organ timing signal associated with an inspected organ.

Abstract: A medical device such as a wire guide has a lubricious and/or therapeutic coating adhered to an etched, carbonaceous polymeric surface, for example a sodium-etched polymer surface. A method for preparing a lubricious and/or therapeutic coating on a medical device includes etching a polymeric portion of the device to create a carbonaceous surface and applying a lubricious and/or therapeutic coating on the etched surface.

Abstract: A catheter system including a housing and a first drive mechanism supported by the housing configured to impart movement to a first catheter device is provided. The first drive mechanism is moveable between an engaged position in which the first drive mechanism engages the first catheter device and a disengaged position in which the first drive mechanism does not engage the first catheter device. The catheter system includes a second drive mechanism supported by the housing configured to impart movement to a second catheter device. The second drive mechanism is moveable between an engaged position in which the second drive mechanism engages the second catheter device and a disengaged position in which the second drive mechanism does not engage the second catheter device. The catheter system includes a manual control configured to allow a user to manually move the first drive mechanism and the second drive mechanism between the engaged and disengaged positions.

Abstract: A robotic catheter system is provided. The catheter system includes a housing, and the housing has a sidewall and a longitudinal axis. The catheter system includes a recess formed in the sidewall of the housing and a drive mechanism supported by the housing. The drive mechanism is configured to impart movement to a catheter device. The catheter system includes a first channel configured to receive a catheter device, and the first channel has a opening located within the recess.

Abstract: A catheter system including a housing and a drive mechanism supported by the housing is provided. The drive mechanism includes an engagement structure configured to engage and to impart movement to a catheter device. The engagement structure defines a path for the catheter device, and the engagement structure is moveable between an engaged position in which the engagement structure engages the catheter device and a disengaged position in which the engagement structure does not engage the catheter device. The catheter system includes a biasing element configured to bias the engagement structure toward the engaged position, and the biasing element is aligned generally parallel to the path defined by the engagement structure.

Abstract: A guidewire catheter includes: a sheath for passing a guidewire therethrough; an operation section connected to an end of the sheath and having a through-hole for passing the guidewire therethrough; a guidewire adapter connected to the operation section and capable of freely extending or retracting relative to the operation section along the axial line of the through-hole, the guidewire adapter grasping the outer periphery surface of the guidewire projecting from the through-hole, and the guidewire adapter being capable of guiding and moving the guidewire relative to the operation section in an axial direction and a circumferential direction of the through-hole; a bar-shaped slide section formed on one of the operation section and the guidewire adapter in the exterior of the through-hole, the slide section being disposed along a line which is parallel with the axial line of the through-hole; a receiver formed on the other one of the operation section and the guidewire adapter and being capable of moving and s

Abstract: A guide wire includes a wire body having a tapered portion disposed on a distal end portion thereof and having an outside diameter progressively reduced toward a distal end thereof. The guide wire also includes a coil having a first coil portion covering an outer circumferential surface of the tapered portion and a second coil portion disposed adjacent to a proximal end of the first coil portion and covering an outer circumferential surface of a constant-outside-diameter portion of the wire body. Initial tensile forces of the first coil portion are greater than initial tensile forces of the second coil portion.

Abstract: A guide wire includes a distal end side portion formed of a first metallic material, a proximal end side portion formed of a second metallic material higher in rigidity than the first metallic material, and an intermediate portion provided between the distal end side portion and the proximal end side portion and formed of a mixture of the first metallic material and the second metallic material. The intermediate portion includes a gradient physical property portion in which the content of the second metallic material increases from the distal end side toward the proximal end side.

Abstract: A controller for use with a guidewire, such as a vascular guidewire, provides a mechanism for gripping and applying a torque to the guidewire without the need to thread the guidewire axially through the controller and at a location close to a point of access of the guidewire. In one embodiment, the controller includes a side-access, multi-part assembly including a collett or other gripping element that applies a uniform radially inward force on the guidewire. In another embodiment, for use with guidewires having active electrically controllable elements, the controller integrally or removably incorporates a switch or other mechanism to initiate an energized state. The controller thereby permits, among other advantages, ergonomic, single-handed control of an electronically steerable guidewire, including axially displacing, torquing and steering the guidewire.

Abstract: A wire guide includes a mandrel that has a proximal portion and a distal portion. A first coating with a low coefficient of friction is disposed on the proximal portion of the mandrel. A second coating is disposed on the distal portion of the mandrel, where the second coating provides a sub-structure. A third coating is disposed on the second coating, where the third coating comprises a surface that allows for easy maneuverability of the wire guide. The first coating on the proximal portion provides enough lubricity to keep the wire guide from becoming bound or stuck in a catheter or medical device while still allowing a user to have a good grip of the wire guide. The second coating on the distal portion provides lubricity for the wire guide, which allows the user to easily maneuver the wire guide through a vascular anatomy.

Abstract: A bifurcated catheter includes a first catheter branch having a first distal portion and a second catheter branch having a second distal portion. The first and second distal portions are linked together for delivery to the bifurcated region. Upon delivery to the bifurcated region, the first and second distal portions are released from each other such that the first and second catheter branches may be tracked into first and second vessel branches, respectively. The first and second distal portions can be linked together by inserted the second distal portion into a skive in the first distal portion, adhesive beat bonding the distal portions together, a coil wrapped around the distal portions, or a spiral cut in the first distal portion sized and shaped to received a guidewire.

Abstract: A guidewire having an embedded matrix polymer construction and methods of making and using the same. The guidewire may include a core wire or member having a proximal region and distal region, a jacket disposed over the distal region, and a coil disposed over the jacket. The coil may include a coating and may be embedded within the jacket.

Abstract: A rapid exchange catheter comprises a guide wire lumen including a substantially sealed portion in which a lumen wall extends around an entire periphery thereof and a channel portion including a channel opening the lumen to an exterior of the catheter, wherein a width of the channel is less than a maximum width of the channel portion. A guide wire ramp extends into the channel portion, with the ramp extending further into the lumen of the channel portion as a distal end of the ramp is approached.

Abstract: The present disclosure is directed to a method of facilitating treatment via a vascular wall defining a vascular lumen containing an occlusion therein. The method may include providing an intravascular device having a distal portion and a longitudinal axis and inserting the intravascular device into the vascular lumen. The method may further include positioning the distal portion in the vascular wall, rotating the intravascular device about the longitudinal axis, and advancing the intravascular device within the vascular wall.

Abstract: A bi-directional steerable guidewire having a deflectable distal tip which comprises a longitudinal hypotube and an interlocking spring coil attached to the distal end of the hypotube and also includes a longitudinally movable deflection member which is attached to the distal end of the spring coil and a tip retaining member which extends from the distal end of the hypotube to the distal end of the spring coil for providing very precise deflection of the distal tip.

Abstract: A movable-core guidewire including a proximal portion and a distal portion. The proximal portion includes a proximal hollow tube. The distal portion includes a coil coupled to the proximal hollow tube and an elastomeric distal tube disposed within the coil. A core wire is disposed within the hypotube. The core wire is movable between a distal position wherein a portion of the core wire is disposed in the distal tube and a proximal portion wherein the core wire is removed from the distal tube. A method is also disclosed for advancing the guidewire to the treatment site.

Abstract: A dual function catheter handle is provided for simultaneous movement of two control wires. The catheter handle has a handle housing having proximal and distal ends and a generally hollow interior. A core is mounted in the interior of the handle housing, the core having a longitudinal slot therethrough. A first moveable member is provided with a proximal end mounted in the interior of the handle housing and a distal end extending outside the handle housing. The first moveable member is longitudinally moveable relative to the handle housing. A second moveable member is mounted in the longitudinal slot of the core and is longitudinally moveable relative to the core and handle housing. The second moveable member has a threaded surface. A rotatable member is mounted on the handle housing. The rotatable member has a threaded inner surface that mates with the threaded surface of the second moveable member so that rotation of the rotatable member causes longitudinal movement of the second moveable member.

Abstract: A guiding catheter includes an inner guide movably disposed within an outer guide. Both inner and outer guides include inner and outer balloons, respectively, located at the distal tip of the guides. The inner guide balloon is fluted, thereby allowing blood to flow past the implanted balloon when inflated. The outer balloon is substantially annular in shape and is deployable as an occlusion balloon. Various sensors can be provided at the distal end of the guiding catheter to assist in locating a destination vessel or structure of interest.

Abstract: A series of embodiments of multi-lumen, multisegmented (or variable diameter) catheters and associated multi-channel flow control and measurement systems and methods for simultaneous delivery of a medium to a plurality of locations is described. The need for precise, stable reliable, and repeatable flow control in therapy delivery catheters is crucial to the efficacious treatment of the clinical manifestations of peripheral vascular disease (PVD) and other such maladies. Such treatments may involve the placement of multi-lumen catheters into peripheral arterial trees, with the subsequent need to govern the flow dynamics within each individual lumen of the multi-lumen device in such a way that an optimum distribution of the agent is achieved intra-arterially. Combinations of pumps, flow monitors, pressure monitors, feedback loops and related hardware and software collectively capable of achieving this goal are described.

Abstract: A guide catheter employs a retractable inner sheath movably disposed within an open lumen of an outer sheath. The inner sheath includes a pre-formed distal end and an open lumen adapted to receive a payload. The inner sheath is translatable and rotatable relative to the outer sheath. The inner sheath conforms to the outer sheath shape until it is distally extended beyond the outer sheath. The outer sheath contains a steering tendon that can be used to adjustably deflect the outer sheath. The guide catheter further includes a proximally attached guide handle. A steering handle can be pivotably connected to the guide handle. The steering handle is connected to the steering tendon and can apply a tensile force to the steering tendon for adjustably deflecting the outer sheath. A catheter according to the present invention provides an improved system for locating and cannulating cardiac venous structures, particularly the coronary sinus via the right atrium.

Abstract: An access tube has a central passage and at least one lumen extending axially between the central passage and an outside wall of the access tube. The lumen carries therein a piercing member for accessing an anatomic space, such as a pericardial space between the parietal pericardia and the visceral pericardia. While the access tube is positioned against the parietal pericardium, a distal end of the piercing member engages and penetrates the parietal pericardium. The distal end of the piercing member entering the anatomic space can then allow the piercing member to advance and form into a supporting structure to create a working space. After the working space is created, an access device can be introduced through the access tube into the pericardial space to perform a variety of procedures inside a patient.

Abstract: An apparatus and method for guiding a needle in conjunction with a biopsy using a medical imaging device, where an open-ended needle guide with an adjustable pivoting multi-gauge needle stop is used to guide a needle during insertion and during a tilting of the needle with respect to the medical imaging device.

Abstract: Forceps with a pair of scissor-like arms that are pivotally connected to each other and that continue past the pivot to form a catheter guide. At least two and preferably three bends are disposed in the arms immediately before the pivot, which allow the medical professional to place the guiding end of the forceps in the correct place while maintaining good visual contact with the patient's vocal cords. An alternative embodiment provides a fourth bend near the guiding end of the forceps that allows for easier insertion of a catheter in some patients, such as children.

Abstract: A diagnostic catheter having both a guidewire lumen and at least one contrast lumen is disclosed. In one embodiment, the contrast lumens allow the user to deliver contrast to a target area within the patient without removing the guidewire. Preferably, a plurality of contrast exit ports are included along the length of the catheter body to evenly and consistently distribute contrast into the blood stream, thereby providing improved visualization during radioscopy.

Abstract: A system and method to track movement of a tool in percutaneous replacement of a heart valve of a subject is provided. The system includes an imaging system, a navigation system operable to track movement of the tool through the patient and to illustrate a representation of a position the tool in spatial relation relative to images acquired by the imaging system, and a controller. The controller is operable to identify one of a series of pathways to move the tool through a patient in percutaneous replacement of the heart valve, to identify a sequence of models illustrative of the one of the plurality of pathways, to detect the position of the tool within a threshold of one of the models in the sequence, and to generate display including a representation of the tool superimposed relative to the model within the threshold.

Abstract: A steerable balloon catheter including a balloon catheter supported by a steerable guidewire having a deflectable distal tip. The guidewire comprises a longitudinal hypotube and a spring coil attached to the distal end of the hypotube and includes a longitudinally movable deflection member which is attached to the distal end of the spring coil and a tip retaining member which extends from the distal end of the hypotube to the distal end of the spring coil for providing very precise deflection of the distal tip of the balloon catheter.

Abstract: Medical imaging and navigation system including a processor, a medical positioning system (MPS), a two-dimensional imaging system and an inspected organ monitor interface, the MPS including an imaging MPS sensor, the two-dimensional imaging system including an image detector, the processor being coupled to a display unit and to a database, the MPS being coupled to the processor, the imaging MPS sensor being firmly attached to the image detector, the two-dimensional imaging system being coupled to the processor, the image detector being firmly attached to an imaging catheter.

Abstract: An apparatus includes an optical element, a GRIN lens, and a detector. The optical element has a first optical aperture. The GRIN lens has first and second ends. The first end of the GRIN lens is positioned to receive light from the first optical aperture. The detector is configured to measure values of a characteristic of light emitted from the first end in response to multi-photon absorption events in a sample illuminated by light from the second end of the endoscopic probe.

Abstract: A disposable high density optically readable polydeoxynucleotide array with integral fluorescence excitation and fluorescence emission channels is described. The compact array size allows integration into several types of interventional devices such as catheters, guidewires, needles, trocars and may be used intraoperatively. Highly sensitive monitoring of the metabolic and disease pathways of cells in vivo under varying chemical, genetic and environmental conditions is afforded.

Abstract: The movement of catheters and guide wires for catheters with the aid of magnets is known from the field of cardiology. Conventional magnets are, as a result of their size, not suited to being inserted into the brain of patient, because the vessels there are smaller than the cardiac vessels. To enable the navigation methods proven in cardiology also to be used in neurology, the invention provides a microcatheter having a guide wire, which features magnetic nanoparticles. The magnetic nanoparticles can be provided in the form of a ferrofluid or also as diamond nanoparticles in powder form. This enables navigation of the guide wire and thus ultimately of the catheter in the brain from the outside by way of magnetic fields.

Abstract: A Catheter Guidance Control and Imaging (CGCI) system whereby a magnetic tip attached to a surgical tool is detected, displayed and influenced positionally so as to allow diagnostic and therapeutic procedures to be performed is described. The tools that can be so equipped include catheters, guidewires, and secondary tools such as lasers and balloons. The magnetic tip performs two functions. First, it allows the position and orientation of the tip to be determined by using a radar system such as, for example, a radar range finder or radar imaging system. Incorporating the radar system allows the CGCI apparatus to detect accurately the position, orientation and rotation of the surgical tool embedded in a patient during surgery. In one embodiment, the image generated by the radar is displayed with the operating room imagery equipment such as, for example, X-ray, Fluoroscopy, Ultrasound, MRI, CAT-Scan, PET-Scan, etc.

Abstract: A magnetic resonance imaging apparatus is provided with one or more electrical accessory devices, for example, catheters (10) or RF body coils (6), which are intended for use during the examination of an object, as well as with a connection lead (13) which is arranged so as to extend through an examination zone (1) of the magnetic resonance imaging apparatus, which zone can be exposed to an RF field, and to connect the accessory device to a connection unit (12). In order to avoid heating of the connection lead (13) due to currents induced in the connection lead by the RF field, which currents could lead to injury of a patient or damage of the accessory device or the connection unit (12), the connection lead (13) comprises at least one lead segment (131, 132, . . . ) which has a length which is limited by at least one inductive coupling element, e.g. a transformer (141, 142, . . . ; 161, 162, . . . ) and is unequal to n*/2, where denotes the RF wavelength and n=1, 2, 3, . . . .