Source: http://www.allindianpatents.com/patents/241854-a-phase-shifter-comprising-toroid-assembly
Timestamp: 2018-10-22 12:42:57
Document Index: 485046531

Matched Legal Cases: ['art 3', 'art 3', 'art 3', 'art 3', 'art 3', 'art 3']

Indian Patents. 241854:"A PHASE SHIFTER COMPRISING TOROID ASSEMBLY"
"A PHASE SHIFTER COMPRISING TOROID ASSEMBLY"
This invention relates to a phase shifter comprising a toroid assembly (4) disposed into a housing assembly (1) characterized in that stepped holes (10) being provided at the curvature (11) of the groove (12) provided in said lower part (3) of the housing (1), threaded holes (8) provided in said lower part (3) of the housing (1) towards the toroid assembly (4) to secure the cover (2) having corresponding holes (9) with the said housing (1) to make firm contact between said cover (2) and toroid assembly (4).
This invention relates to a phase shifter, particularly this invention relates to an improvement in or relating to a phase shifter module having improved insertion loss characteristics and reduced rms phase error.
Phase shifter, particularly microwave phase shifter is an important component used for the construction of electronically scanned antenna called the "Phased Array". The phased array referred herein, consists of a number of radiators each excited with a radio frequency (RF) signal. By adjusting the phase of radio frequency (RF) signal delivered to each radiator electronically, the beam position can be changed within a few microseconds. In a practical system, the phase of the radio frequency (RF) signal is adjusted with the help of a phase shifter, particularly, microwave phase shifters inserted prior to the radiating element.
Depending on the application, several types of phase shifters are known in the prior art. Such known microwave phase shifters of the prior art include the semiconductor phase shifters such a sp—i—n diode and metal semiconductor filed effect transistor, referred herein after as MESPET phase shifters and the ferrite phase shifters, particularly, toroid ferrite phase shifter.
The semiconductor phase shifters, known in the prior art are generally con-fined to the applications involving low transmitted power- This limitation of the semiconductor phase shifter is overcome by ferrite phase shifters, particularly, toroid ferrite microwave phase shifter.
The ferrite phase shifters, particularly, toroid ferrite microwave phase shifters, known in the prior art, can be classified into two categories. The category-l is of non-reciprocal ferrite phase shifters and the category-2 is of reciprocal ferrite phase shifters. Generally the phase shifter comprises a toroid assembly disposed in a housing assembly with a precisely controlled metallisation provided thereon.
The non-reciprocal ferrite phase shifters of category-l are favored in the systems operating over broad frequency bands, having high average radio frequency (RF) power requirements of requiring rapid beam switching. However, the disadvantage of such known phase shifters is that, their application is limited to the pulsed type transmit/receive systems, where sufficient time is available for the switching operation between the
transmit and receive interval. This limitation in application is due to their non-reciprocal nature of phase shift characteristics.
The reciprocal phase shifters of category-2, known in the prior art, are useful primarily for short range CW radars.
The non-reciprocal phase shifters, as known in the prior art, are reported with several configuration in the literature. These configurations include rectangular toroid in a rectangular waveguide, helix type phase shifter and circular toroid in circular waveguide.
The most commonly used non-reciprocal /reciprocal phase shifters in the prior art are single toroid phase shifters, which find their various practical applications. However, the main disadvantage of known such single toroid phase shifters are their heavy weight and large size. These drawbacks of such known toroid phase shifters limit their applications primarily to the ground based system.
Another disadvantage of such known single or dual or both toroid phase shifters of the prior art is of their extremely small size and
dimensions of the toroid hale. The size and dimensions of the toroid hole are very crucial factors in case of toroid phase shifters. The figure of merit is observed to be better and improved, when the toroid hole is loaded with a high dielectric constant material. Such type of loading is possible only at lower frequencies, for example at S and L bands. However, as frequency increases, it becomes extremely difficult to load the toroid hole with high dielectric constant material due to the extremely small size and dimensions of the toroid hole. If this drawback is overcame, then it results in other disadvantages of the single toroid phase shifters, such as poor figure of merit and large size of the toroid and toroid hole at required higher frequencies including the X-band.
Yet another disadvantage is that the metallisation of the toroid assembly is very costly and combersion.
Still another disadvantage is that threaded holes for securing cover with the housing are provided in the housing at a distance from the toroidal assembly and near the outer sides and therefore the contact between the cover and toroidal assembly is not very good and radiation losses occur during the use of the phase shifter.
A further disadvantage of such a known single or dual or bath toroid phase shifters of the prior art is the difficulty to achieve repeatable results since the toroidal hole loading cannot be controlled precisely.
Another disadvantage of such known single/dual toroid phase shifters is that it results in higher insertion loss and rms phase error and requires higher switching time.
Yet another disadvantage is that the capper wire gets short-cut, when passed through the toroid hole provided for such purpose in the base housing of the toroid ferrite microwave phase shifter.
Still another disadvantage is that the known housing assemblies of single or dual toroid ferrite microwave phase shifters generally needs the metallisation and the thickness of metallisation, that is, of conducting layer is required to be controlled precisely.
Therefore, the primary abject of this invention is to propose a phase shifter module for operation at higher f requency range with low insertion lasses.. -The phase shifter, as referred herein, may be single or dual toroid ferrite phase shifter, and or may be non-reciprocal or reciprocal toroid ferrite phase shifter.
Another object of the present invention is to propose a toroid ferrite microwave phase shi-fter module which can overcome the disadvantages associated with the known art.
Yet another abject of this invention is to propose a phase shifter and where the metallisation is not at all required.
Still another object of this invention is to propose a toroid ferrite microwave phase shifter module which is small in size and light in weight, easy to fabricate on industrial scale and offers faster switching time.
Another object of this invention is to propose a toroid ferrite microwave phase shifter module which provides improved figure of merit and of repeatable results. The figure of merit means phase shift per dB of insertion loss.
A further object of this invention is to provide a housing assembly for toroid ferrite microwave phase shifter module having considerable reduction of channel dimensions, which in turn lead to overall size reduction and lower weight and obviates disadvantages associated with the prior art. Further the housing has been improved suitably for use for the ground based and airborne phased array radars.
According to this invention there is provided a phase shifter comprising a toroid assembly disposed into a housing assembly characterized in that stepped holes being provided at the curvature of the groove provided in said lower part of the housing, threaded holes provided in said lower part of the housing towards the toroid assembly to secure the cover having corresponding holes with the said housing to make firm contact between said cover and toroid assembly.
In accordance with this invention the phase shifter/toroid ferrite microwave phase shifter has a toroid assembly, which is disposed into a housing assembly, Stepped holes are provided in the housing at the channel having larger width at either ends of the wave-guide housing. Specifically, the stepped holes according to this invention are of the special construction and are provided so as to minimize the insertion loss and reduce rms phase error. Further the threaded holes are provided in the lower housing near the toroid assembly disposed in the housing to secure the top cover with the lower housing so as to make firm contact there between, Further the Stepped holes and threaded holes are so designed that the metallisation of the housing as well as the toroid assembly is not required.
firm contact there between. Further the stepped holes and threaded holes are so designed that the metallisation of the housing as well as the toroid assembly is not required.
An Improved phase shifter according to a preferred embodiment is herein described and illustrated in the accompanying drawings wherein:-
Fig-1 shows the prospective view of the phase shifter,
Fig-2 shows the sectional view of the phase shifter; and
Fig-3 shows the sectional view of the stepped hole provided in the lower housing.
Referring to the drawing particularly Fig.l the phase shifter has a having a cover 2 and a lower parts/base housing 3 for accommodating a toroid assembly in the central channel 5 provided in the lower part 3 of the housing 1 and as shown in Fig.2. Matching elements 6 consisting of a plurality of transformers are provided between the toroid assembly 4 and antenna element 7 of the phase shifter. These features do not constitute the inventive features of the present invention. Specifically according to this invention and as shown in Fig.l the threaded holes 8 are provided in the lower part of the housing 1 near toroid
assembly 4 disposed in the channel 5 provided in the housing 1. Corresponding holes 9 are provided in the cover 2 of the housing i for securing the cover 2 with the lower part 3 of the housing 1 to establish a thorough/firm contact between the cover 2 and the lower part 3 of the housing 1. The threaded hales 8 are provided near the toroid assembly so as to avoid the radiation losses and has phase error during the use of the phase shifter. Stepped/toroid holes 10 are provided in with lower part 3 of the housing 1 such that the inner ends thereof are opening in the curvature portion 11 provided between the channel 5 and grooves 12 provided at the ends of the lower part 3 of the housing 1. The grooves 12 are double in the widths than the widths of the channel 5.
The stepped holes 10 as shown in Fig.3 comprises a hole of small diameter 13 and larger diameter 14 provided in the lower portion 3 of the housing 1. The small diameter 13 opens at the curvature portion 11 of the groves 12 so as to allow a copper wire 15 therethrough. Means are provided into said hole 14 of larger diameter to keep the copper wire 15 into fixed and predetermined position. The means for holding the copper wire comprises a brass pin 16 is disposed in
the stepped hole 10 for keeping the copper wire into the fixed/predetermined position. A teflon bead 17 is provided to support the brass pin 16 in the stepped hole 10 such that a cavity 18 between the hole 13 and the hole 14 is created so as to stop the contact between the brass pin 16 and metallic base housing. The brass pin 16 and teflon bead 17 are preferably of tubular shape. The copper wire 15 is provided to constitute the connecting terminals of the phase shifter on either ends and on either sides of the lower part 3 of the housing 1 so as to connect the toroid assembly 4 to the outer connecting wires. The toroid assembly comprises a conventional toroid assembly.
The process of manufacture of the phase shifter comprises placing the toroid assembly in the channel provided in the lower part of the housing assembly. Copper wires connected with toroid assembly at either ends and on either sides are then passed through the holes provided at either ends and on either sides the phase shifter so as to constitute the connecting terminals of the phase shifter. After placing the toroid assembly into the lower position of the housing the hole assembly is subjected to the step of metallisation for facilitating firm contact between the
cover and the lower part of the housing upon securing the cover with the and toroid assembly by means of screws. This process is a conventional process for preparing a phase shifter.
Specifically according to the present invention the threaded holes are provided in the lower part of the housing and towards the toroid assembly for securing the caver having corresponding holes therein such that to make a firm contact between the cover and the toroid assembly disposed in the lower part of the housing and thus the metallisation of the lower part of the housing is avoided. Further the special kind of stepped holes are provided in the lower part of the housing such that to pass the copper wires in a fixed and predetermined position so as to avoid a short-cut of the copper wire during passing of the copper wire
through the toroid holes and repeated use of the phase shifter.
Thus it is seen that by providing the stepped holes and threaded holes of the special design all the disadvantages associated with the prior art have been obviated. Further the metallisation of the housing as well as the toroid assembly is not needed.
I CLAIMS;
1.	A phase shifter comprising a toroid assembly (4) disposed into a housing assembly (1) characterized in that stepped holes (10) being provided at the curvature (11) of the groove (12) provided in said lower part (3) of the housing (1), threaded holes (8) provided in said lower part (3) of the housing (1) towards the toroid assembly (4) to secure the cover (2) having corresponding holes (9) with the said housing (1) to make firm contact between said cover (2) and toroid assembly (4).
2.	A phase shifter as a claimed in claim I wherein said stepped holes (10) comprises a hole having lesser diameter (13) and larger diameter (14) opening outwardly on the sides of the lower part (3) of the housing (1) to allow passing of the copper wire (15) there through, means are provided to keep the cooper wire (15) in the fixed and predetermined position.
3.	A phase shifter as claimed in claim 2 wherein the hole of lesser diameter (13) is opened at the curvature (11) of the groove (12) provided at the ends of said lower part (3) of the housing (1).
4.	A phase shifter as claimed in claim 2 wherein said means comprises a brass pin (16) supported by a teflon bead (17) adapted to be accommodated into said hole (13) of larger diameter (14).
5.	A phase shifter as claimed in claim 4 wherein said pin (16) is disposed into said bead (17) to provided a cavity (18) between the housing (1) and said brass pin (16).
6.	A phase shifter substantially as herein described and illustrated with reference of accompanying drawings.
2813-del-1996-abstract.pdf
2813-del-1996-claims.pdf
2813-del-1996-correspondence-others.pdf
2813-del-1996-correspondence-po.pdf
2813-del-1996-descraption (complete).pdf
2813-del-1996-drawings.pdf
2813-del-1996-form-1.pdf
2813-del-1996-form-19.pdf
2813-del-1996-form-2.pdf
2813-del-1996-form-26.pdf
2813-del-1996-form-3.pdf
2813-del-1996-form-6.pdf
2813/DEL/1996
THE CHIEF CONTROLLER, RESEARCH & DEVELOPMENT ORG.
B-341 SENA BHAWAN, DHQ P.O. NEW DELHI-110011, INDIA.
1 SHIBAN KISHEN KOUL CENTRAL FOR APPLIED RESEARCH IN ELECTRONICS, INDIAN INSTITUTE OF TECHNOLOGY, HAUZ KHAS, NEW DELHI-110016, INDIA.
2 BHARATHI BHAT CENTRAL FOR APPLIED RESEARCH IN ELECTRONICS, INDIAN INSTITUTE OF TECHNOLOGY, HAUZ KHAS, NEW DELHI-110016, INDIA.