The undersigned confirm that they have read and nominate the Postgraduate Studies Program for acceptance of this thesis in order to fulfill the requirements for the degree indicated. The three antenna arrays presented in the thesis are single band, dual band and small size high gain CDRA arrays. Second, dual band and small size array antennas are excited through the 2.6 mm wide microstrip line designed on a flame retardant (FR4) substrate with es2 = 4.9.
In addition to the CST design, the equivalent conjoined element circuit of the small array antenna is modeled to verify antenna feasibility using Advanced Design System (ADS) software. The three array antennas designed: single-band, dual-band and small high-gain antennas have been manufactured. The measured gain of the fabricated antenna prototypes is approximately 10.0 dBi, which meets the requirements for indoor and outdoor wireless local area network (WLAN) applications.
In accordance with the terms of the Copyright Act 1987 and the university's IP Policy, the copyright of this thesis has been reassigned from the author to the university's legal entity. Appropriate acknowledgment should always be given for the use of any material included in this thesis or derived from the final.
Effects of Aperture Slot Length on the Top Radiating Element of
Effects of Aperture Slot Length on the Bottom Radiating Element of
An equivalent circuit with coupled elements of a small antenna array is designed using ADS and. The single-band array CDRA is designed to improve the performance of the single-element CDRA presented in Section 3.2. An important step in the characterization of a CDRA single-band array is the determination of its design parameters.
The proposed geometries of the CDRA single-band array and rectangular-aperture slots are shown in Figure 3.6. Geometry of an aperture-coupled CDRA single-band array (a) Rectangular slots without DRA (b) Complete the proposed design. The proposed geometries of the two-band array CDRA and slits with rectangular apertures are shown in Figure 3.8.
The equivalent composite element circuit of the proposed small CDRA array has also been modeled to validate the antenna operation. The equivalent pooled element circuit of a small CDRA array, shown in Figure 3.11, is used to analyze the effects of slot length on Rr, Lrand Cr of the dielectric resonator.
URIF
The equivalent lumped element circuits of proposed single element CDRA and small size high gain CDRA array are modeled to verify the feasibility of the antennas. The Matlab programs for the various equations (2.38) through (2.50) are used to determine the RLC parameters for. The resonant resistance Rr, the inductance Lr, and the capacitance Cr of the dielectric resonators are determined using equations (2.38) through (2.40).
The Matlab program used to determine the radiation conductance Grm and susceptance of the fringe field capacitance Bm of microstrip line is given as. The interconnection between radiating elements of a small size high-gain CDRA array is determined using equations (2.44) to (2.50). In practice, the most commonly quoted parameter in relation to antennas return loss Su- Antenna return loss Su represents how much power is reflected from the antenna, and is therefore known as the reflection coefficient.
The example of return loss Su of a small CDRA array shown in Section 3.6, measured using the above procedure, is shown in Figure B2. The return loss of -42 dB is achieved by a fabricated prototype small CDRA array with a resonance frequency of 5.0 GHz with a bandwidth of 1.2 GHz. The comparison between the measured and simulated efficiency losses of small CDRA arrays is shown in Figure 4.14.
It is defined as the ratio of an antenna's intensity (usually in the direction of peak radiation) to an isotropic antenna. The AUT or antenna undertest is the one we are interested in finding out the gain (the designed antenna). The unknown gain antenna is actually an antenna whose gain we don't need to know exactly, but which should at least have enough dynamic range to transmit all the way to the AUT.
Since the networks under analysis are often used by insertion into a transmission medium with a common characteristic reference impedance, S parameters have the advantage of being directly related to commonly specified performance parameters such as insertion gain and return loss. Follow the procedure below to measure the antenna gain using the Voltage Network Analyzer (VNA), as shown in Figure CI. Connect the "unknown gain antenna" to port 1 (transmitter) of the network analyzer and the reference antenna to port 2 (receiver).
Record the new S2j values. This is the gain/loss Grdative of the AUT relative to the
The equation used to calculate the gain of AUT, is given as
Mount the "unknown gain antenna" and the reference antenna on two stands as shown in Figure C2
The experimental setup is performed using steps (3) - (9) of the gain transfer method shown in Appendix C. The R2i value is recorded and the gain of the reference antenna is added to determine the gain of the AUT (small size CDRA array). The radiation pattern of high gain small size CDRA array is determined by rotating the AUT antenna (small size CDRA array) 360° with step size of 15°.
The radiation pattern of a small CDRA array at 5.6 GHz is discovered by plotting the values of Table IC using sigma plotting software, as shown in Figure C3. The antenna is an important part of radio communication, remote sensing and radio location systems. By measuring the signal strength characteristics of the antenna, the compliance of the antenna can be verified.
Antenna measurement techniques involve testing antennas to ensure that the antenna meets specifications or simply to characterize it. The main purpose of open space measurements is to measure the signal strength of the designed antenna and compare it to the signal strength of the standard monopole antenna. The following procedure for measuring the signal strength of the antenna in open space as shown in Figure DI is given as.
Connect the "monopole antenna" to the signal generator and designed antenna with the spectrum analyzer
The equation IC is used to calculate the distance between the two antennas as given.
