| 1. |
- Carpenter, Sona, 1983, et al.
(författare)
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A G-Band (140-220 GHz) planar stubbed branch-line balun in BCB technology
- 2013
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Ingår i: 2013 3rd Asia-Pacific Microwave Conference, APMC 2013, Seoul, South Korea, 5-8 November 2013. - 9781479914746 ; , s. 273-275
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Konferensbidrag (refereegranskat)abstract
- A G-Band planar stubbed branch-line balun isdesigned and fabricated in 3μm thick BCB technology. Thistopology of the balun does not need thru-substrate via hole orthin-film resistor which makes it extremely suitable for realizationon single-layer high-resistivity substrates commonly used atmillimeter-wave or post-processed BCB layers on top of standardsemi-insulating wafers. The design is simulated and validated bymeasurements. Measurement results on two fabricated back-tobackbaluns show better than 10 dB input and output return lossand 3.2 dB insertion loss from 140 to 220 GHz.
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| 2. |
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| 3. |
- Hammar, Arvid, 1986, et al.
(författare)
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A 340 GHz High Gaussicity Smooth Spline Horn Antenna for the STEAMR Instrument
- 2014
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Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781479935383 ; , s. 649-650
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Konferensbidrag (refereegranskat)abstract
- We present the design, fabrication and measure-ments of a smooth walled spline feed horn antenna for the satellite borne climate research instrument STEAMR operating at 340GHz. A method has been developed which, for a certain desired beam waist, can be used to optimize the horn profile for high Gaussicity and ultra-low sidelobes. The simulated performance of the horn achieves a beam waist of 1.9 mm over the band 323-357 GHz with Gaussian coupling efficiency exceeding 98%. The peak cross-polar sidelobes are below -28 dB over the required frequency band. For cost effective manufacturing with high repeatability, the smooth wall spline profile is drilled in out from a metal block using a custom made broach. To validate the design and fabrication, planar measurements of the phase and amplitude have been performed and from measured E-field vital horn parameters have been extracted.
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| 4. |
- Hammar, Arvid, 1986, et al.
(författare)
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THz smooth-walled spline horn antennas: Design, manufacturing and measurements
- 2016
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Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016, Fajardo, Puerto Rico, 26 June - 1 July 2016. - 1947-1491. - 9781509028863 ; , s. 1341-1342
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Konferensbidrag (refereegranskat)abstract
- We describe a versatile and cost-efficient method for producing smooth-walled spline horn antennas for applications in THz radiometry. Specifically, the development of four different horns for radiometer receiver applications at frequencies 120, 183, 340 and 874 GHz is presented. General methods for efficient optimization of the spline profiles have been developed which enable the horn designs to be tailored to each application. All four designs display high Gaussicity (typically ∼98%). Manufacturing methods based on numerical milling in splitblocks, lathing and drilling have been tested and compared. Milled splitblock horns with integrated receiver circuits (Shottky mixers in this case) allow for lower losses in the receiver system at the expense of higher cross-polarization levels. The radiation pattern of three designs at 183, 340 and 874 GHz have been measured using planar and rotational scanners.
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| 5. |
- Karandikar, Yogesh, 1982, et al.
(författare)
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A 874 GHz Mixer Block Integrated Spline Horn and Lens Antenna for the ISMAR Instrument
- 2015
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Ingår i: 9th European Conference on Antennas and Propagation, EuCAP 2015, Lisbon, Portugal, 13-17 May 2015. - 9788890701856
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present the design of a 874 GHz mixer block-integrated antenna for the ISMAR Instrument. The spline horn antenna with a dielectric lens (Teflon) is used to fulfill the requirement of an on-axis Directivity exceeding 32 dBi. The well designed spline horn offers very high Gaussian Coupling, exceeding 97%. This property of spline horn further helps to achieve very rotationally symmetric beam even after the lens with very low cross-polarization (
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| 6. |
- Karandikar, Yogesh, 1982, et al.
(författare)
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A compact 340 GHz 2x4 patch array with integrated subharmonic gilber core mixer as a building block for multi-pixel imaging frontends
- 2014
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Ingår i: Technical Digest - IEEE Compound Semiconductor Integrated Circuit Symposium, CSIC. - 1550-8781. - 9781479936229
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Konferensbidrag (refereegranskat)abstract
- For linear multi-pixel imaging systems, a linear stack of pixels comprising of an antenna and a heterodyne receiver are needed. Such pixels can be realized using MMIC processes. The main constraint for such multi-pixel system is a compact array of pixels giving high coupling to quasi-optics used for focusing. This paper addresses this trade-off and presents a novel solution based on beam synthesis of two consecutive subarrays. One such sub-array along with heterodyne receiver is described as half-pixel in this paper and it is realized using 2x4 patch array and Gilbert core sub-harmonic mixer using a 250nm DHBT process. The patch array has ohmic loss better than 8 dB and mixer conversion loss is 6-8 dB over 320-350 GHz RF band. The chip size is 1mm x 2mm and therefore for 7 simultaneous beams a MMIC of 8 half-pixels is foreseen.
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| 7. |
- Karandikar, Yogesh, 1982, et al.
(författare)
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Compact integration of sub-harmonic resistive mixer with differential double slot antenna in G-band using 50nm InP-HEMT MMIC process
- 2012
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Ingår i: 2012 IEEE Compound Semiconductor Integrated Circuit Symposium, CSICS 2012, La Jolla, CA, 14 - 17 October 2012. - 1550-8781. - 9781467309295
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Konferensbidrag (refereegranskat)abstract
- Sub-Harmonic resistive HEMT based mixers in Gband have been designed and integrated with Double Slot Antenna in Differential Configuration for the first time. This novel topology shows compact integration of active devices between antenna ports while achieving 25 GHz bandwidth around 200 GHz. The dual-gate 50nm x 15um InP HEMT used in the design achieves the conversion loss of 15 dB with +3 dBm LO power drive. Furthermore, a similar topology when used as a Harmonic mixer using a single gate device offers 16.5 dB conversion loss for +4 dBm LO power. For compact integration, via hole matching on slot antenna is also presented.
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| 8. |
- Karandikar, Yogesh, 1982
(författare)
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Comparisons of different descrambler/ power combining boards layout for multi-port, decade bandwidth Eleven feed
- 2010
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Ingår i: 4th European Conference on Antennas and Propagation, EuCAP 2010; Barcelona; Spain; 12 April 2010 through 16 April 2010. - 9788476534724 ; , s. Art. no. 5505128-
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Konferensbidrag (refereegranskat)abstract
- Eleven feed based on parallel folded dipole log-periodic arrays has four differential ports above ground plane. This paper presents different possibilities of combining these ports below ground plane so as to have two unbalanced ports for orthogonal linear polarizations. Also the various ways of combining LNA in these boards is discussed. For radio astronomy applications, where lowest noise is desired, the use of differential LNA and further passive power combining is justified as best possible choice.
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| 9. |
- Karandikar, Yogesh, 1982
(författare)
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Dual Band Prime Focus Feed for Satellite Earth Terminals
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Satellite Communication systems have been studied and developed since long. With more high frequency satellite bands coming in the market, there is a need to develop suchsystems with multi-band or wideband operation with reconfigurable antennas which can provide simultaneous transmit receive capabilities on different polarizations as well as have properties suitable to track the satellite. This thesis is primarily focused on developing a satellite communication system which operates simultaneously over X (7.25-8.4 GHz) and Ka (20.2-31 GHz) band using the new wide band technology referred to as Eleven feed with broad band choke horn. This type of system finds commercial applications in satellite earth terminals for voice, video or data communication for news broadcast or military warfare applications.The first section of this thesis describes basic blocks of such a satellite communication system and emphasizes on the feed with prime focus reflector which is very common type of antenna for these applications. Furthermore, it gives details of the ‘Eleven’ feed geometry formed by two parallel (linear as well as circular) dipoles above ground plane and describes how dipole separation and height above ground plane influence radiation performance characterized by feed aperture efficiency.In order to achieve dual band performance, different technologies like Eleven feed, Hat feed, Choke Horn, stacked patch arrays are briefly discussed in section two and combination of Eleven Feed with Choke Horn giving better than -2dB aperture efficiencies in both bands is considered as potential technology to explore further.Finally, the simulated performance of X band ‘Eleven’ feed integrated with Ka band choke horn is presented in section three. The estimated performance show feed aperture efficiency better than -3dB for prime focus reflector with half subtended angle of 50°. The matching of the antenna impedance to system characteristic impedance is found to bebetter than -15dB in X band and better than -20dB in Ka band.
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| 10. |
- Karandikar, Yogesh, 1982
(författare)
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Factorization of Gaussian Coupling Efficiency and algorithm to compute it
- 2012
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Ingår i: Proceedings of 6th European Conference on Antennas and Propagation, EuCAP 2012. Prague, 26-30 March 2012. - 9781457709180 ; , s. 868-872
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Konferensbidrag (refereegranskat)abstract
- Gaussian Coupling Efficiency (η G) quantifies the amount of radiated power getting coupled to fundamental gaussian beam mode. This paper focus on the computations of η G for antennas from their far-field data. The mathematical analysis presented in the paper shows that the term η G can be factorized into sub-efficiencies namely, BOR 1, spill over, polarization and BOR 1 to Gaussian Coupling. This analysis is based on the definition of Body of Revolution type of antennas (BOR). Based on the analysis, an algorithm is developed to compute η G of Antennas. This algorithm accepts the far-field data of antenna as input and computes the optimum values of Beam Waist ω( o) and it's location (z o) for maximized η G. The algorithm is verified using Smooth Conical Horn. The beam parameters (ω o & z o) of Conical Horn obtained from near field measurements agree well with the beam parameters obtained from the simulated far-field. The 44 Microstrip patch Array is studied using this analysis and found that η G 70% is feasible for 320-350 GHz bandwidth.
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