Slotted waveguide antenna design pdf

Translate PDF. The antenna consists of multiple branchline waveguides with broadwall radiating shunt slots and a main waveguide to feed the branch waveguides through a series of inclined coupling slots. The antenna feed point is located at the center of the main waveguide. Element weights in the array have been calculated bysampling a continuous circular Taylor aperture distribution at the 25 dB sidelobe level in both the E and Hplanes. A commercially available electromagnetic EM simulation tool has been used to characterize the individual isolated slot and that data hassubsequently been used to design the planar array.

The array is finally analyzed in a CST Microwave studio and the measured and simulated results have been found to be in good agreement. Key words : Antenna, Slot, Waveguide. Introduction into the design procedure. Other major research works onlinear and planar slotted waveguide antennas are [5], Slotted waveguide array antennas are widely used for [6].

Isolated slot characterization is required in the de- radars and communication systems [1]. They offer sig- sign of slotted waveguide arrays. Isolated slot admit- nificant advantages in terms of weight, volume, and ra- tance can be measured experimentally [2] or computed diation characteristics. Care must be exercised in calculat- due to their planar, compact, and rugged construction. A ing the individual slot data as minor errors might se- metallic waveguide is a low loss structure and it can verely affect the overall array design.

The dimensions of the slots in the In this paper, the design of a planar slotted waveguide waveguide walls can be controlled to realize the desired array antenna based on the procedure in [3] is discussed.

Longitudinal shunt slot arrays are also at- The design procedure includes bothexternal mutual cou- tractive due to their very low cross-polarization levels. In these design procedures, inter-slot dis- shunt slots acting as radiatorsin the broadwall of a re- tance is one-half the guide wavelength and the wave- duced height waveguide to suppress higher modes.

The guide end is short circuited at a distance of a quar- planar array consists of twelve linear arrays of shunt ter-guide wavelength from the center of the last slot. A feed waveguide is placed beneath the dary. A main waveguide is run across the branch wave- branch waveguides containing radiating slots and power guides to feed them through the inclined-series coupling is coupled from the main waveguide to the branch slots.

Antenna feed is located at the center of the main waveguides through the series of inclined slots. The feed waveguide. Isolated Slot Characterization center of the last inclined coupling slot. ID No. Corresponding Author : Yun-Taek Im e-mail : imyuntaek kaist. For feed slots, the resonant length of the slot as a function of its tilt angle is also required forthe design of the array.

A commercially available EM simulation tool, HFSS, has been used to generate the ba- sic slot data subsequently used in the array design. In the HFSS simulations for the shunt slot, the round ended 2. Resonant length of the broadwall slot versus offset.

The design curve thus generated is shown in Fig. The real and imaginary in Fig. Next, the slot offset is changed and at each step, the slot resonant length is calculated where the imaginary component of the admittance was zero. The coupling slot was also characterized in HFSS for The resulting resonant length of the slot as a function its resonant resistance as a function of the tilt angle.

In of offset is shown in Fig. Normalized admittance of isolated shunt slot versus Fig. Normalized conductance of isolated shunt slot as slot length. Save to Library Save. Create Alert Alert. Share This Paper. Methods Citations. Figures and Tables from this paper. Citation Type. Has PDF. Publication Type. More Filters. The broadening of the main beam is expected since the sidelobes have been forced to go lower. A 20 dB SLR is obtained. The results show an antenna resonance at 3 GHz, and a peak gain of The Y Z-plane gain pattern is shown in Fig.

Table 4. For these displacements values, the obtained SLR is For all the studied examples where all the slots have a fixed length of This is evident by comparing the S11 plot for the case of uniform displacements in Fig. The program takes as input the design frequency, waveguide dimensions a and b, the number of slots, and the highest allowable SLL.

The units are indicated on the program graphical user interface GUI. A screenshot of the program output is given in Fig. This program was used for the examples in Section 3, and for the design in Section 5. Improvements to the program interface are still being done. Figure 9. A screenshot of the python program output. The waveguide in hand has a length of 50 cm. This change was accounted for in the Python computer program, which was used for this design.

To keep the waveguide length of 50 cm, the SWA is designed for a frequency of 3. After initially designing the SWA with the correct uniform distribution displacement, the elliptical slot length has been optimized to get to this resonance frequency.

It is found equal to 48 mm. During Measurement 1, the antenna had some protrusions on the corners of the elliptical slots, which were filed for Measurement 2, resulting in a perfect elliptical shape of the slot. SWA: a designed dimensions in mm , b fabricated. General guidelines for the slots width, length and longitudinal positions were first given.

This procedure was implemented using a Python computer program. A prototype antenna was fabricated and tested, and the results were presented. Gilbert, R. Mailloux, R. Rueggeberg, W. Elliott, R. Antennas Propagat.

Stevenson, A. Baum, C. Al-Husseini, M. El-Hajj, and K. Tai, C. Jasik ed. Oliner, A. Stegen, R. Stevenson, R. Watson, W. Coburn, W.