| 1. |
- Ellgardt, Anders, 1978-
(författare)
-
A Review of Planar Array Antenna Research at KTH
- 2010
-
Ingår i: The Twelth Antennas and propagation Symposium. - Kochi, India : Department of Electronics, Cochin University of Science & Technology.
-
Konferensbidrag (refereegranskat)
|
|
| 2. |
- Ellgardt, Anders, 1978-
(författare)
-
A Scan Blindness Model for Single-Polarized Tapered-Slot Arrays in Triangular Grids
- 2008
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 56:9, s. 2937-2942
-
Tidskriftsartikel (refereegranskat)abstract
- A simple model is presented that predicts scan blindness in the E-plane for single polarized tapered-slot arrays where the elements are positioned in a triangular grid. The blindness occurs when the phase progression along the dielectric substrates is equal to the phase progression of a leaky mode in the structure. A simple equation is presented that estimates the frequency at which the scan blindness occurs for a given angle in the E-plane. This equation is derived from a simple representation of the phased array antenna, but includes the dominant effect of this particular class of scan blindness. The method is shown to agree well with computed results obtained with two different numerical codes.
|
|
| 3. |
- Ellgardt, Anders, 1978-, et al.
(författare)
-
A single polarized triangular grid tapered-slot array antenna
- 2009
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 57:9, s. 2599-2607
-
Tidskriftsartikel (refereegranskat)abstract
- A triangular grid single polarized tapered-slot array antenna for radar applications is studied. Compared with a rectangular grid an equilateral triangular grid allows a larger unit cell without any onset of grating lobes. Since single polarized tapered-slots in triangular grids support guided modes, which cause scan blindness, the increase in unit cell size is smaller than the optimal 15%. The design presented in the paper is capable of scan angles out to 60° from broadside in the E and H planes. To improve the match over the radar band a local minimum in the active reflection coefficient is positioned at the most critical scan direction, resulting in a reflection coefficient that is less than -12 dB in the X-band. To reduce the radar cross section for the cross-polarization an absorbing layer is positioned above the ground plane, which affects some of the guided modes that lead to scan blindnesses. An experimental antenna with 16×16 elements was built, and it was found that the H-plane performance for large scan angles for the finite antenna deviates more than expected from the infinite array approximation. Otherwise both mutual coupling measurements and embedded element patterns agrees well with the numerical results.
|
|
| 4. |
- Ellgardt, Anders, 1978-, et al.
(författare)
-
A study of edge effects in triangular grid tapered-slot arrays using coupling coefficients
- 2010
-
Ingår i: Radio Science. - 0048-6604 .- 1944-799X. ; 45, s. RS2005-
-
Tidskriftsartikel (refereegranskat)abstract
- Edge effects for tapered-slot elements in triangular grid array antennas are studied by using finite difference time domain codes. The S parameters for finite-by-infinite arrays are computed and evaluated for two different edge models and, to evaluate the edge effects, the results are compared with the S parameters for the infinite array. As expected, the largest difference between the results occurs for the elements closest to the edges, because of the missing coupling from nearby elements and the perturbed element currents due to the edge geometry. By using the proposed method it is possible to distinguish between these two edge effects. A method to combine the finite-by-infinite array results and the infinite array results is presented and used to characterize the perturbation caused by the truncation of the infinite array.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Ellgardt, Anders, 1978-, et al.
(författare)
-
Characteristics of a broad-band wide-scan fragmented aperture phased array antenna
- 2006
-
Konferensbidrag (refereegranskat)abstract
- In this paper a phased array antenna is described that is designed with the help of a genetic algorithm for scan angles out to 60° from broadside. The focus is on simplifying the manufacturing of the diagonally adjoining pixels and on numerical results for thin antennas. The effects of the corner to corner contacts are studied and results for two synthesized elements ar Test and measurement requirements on wireless devices
|
|
| 8. |
- Ellgardt, Anders, 1978-
(författare)
-
Computing return loss for arbitrary scan directions using limited scan codes for infinite phase arrays
- 2009
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 45:13, s. 660-662
-
Tidskriftsartikel (refereegranskat)abstract
- Analyzing large phased array antennas using time domain codes is favourable when looking into wideband solutions. This is often done by assuming an infinite array, i.e. a unit cell approach is used. Unfortunately, unit cell based time domain codes using time shifts between cell boundaries have a disadvantage of only being able of analyzing phase shifts corresponding to a beam scanned in the visible space. However, in order to fully characterize the infinite array antenna it is sometimes necessary to compute the active reflection coefficient also for scan directions/phase shifts corresponding to invisible space. Presented in this letter is a new approach on how to do this in a simple manner using unit cell based time domain codes. By extending the size of the computational domain, and include more than one element, phase shifts corresponding to invisible space are included.
|
|
| 9. |
|
|
| 10. |
|
|
