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S. B. Ismail et al.
be mounted directly above the microstrip line without the need to drill or cut a hole
in the ground plane [3, 10, 14].
13.2.3 Basic Antenna Parameters
A dielectric resonator antenna is characterized by various factors such as high efficiency, compact size, and wide operational bandwidth. To meet the characteristics
or specifications, it needs to refer to several parameters. The basic parameters of an
antenna include the radiation pattern, directivity, gain, bandwidth, return loss, and
voltage standing wave ratio (VSWR) [15].
(a) Radiation Pattern
Radiation pattern is a visual expression of an antenna’s radiation properties.
The radiation pattern is commonly known as a mathematical function of the
antenna’s radiation properties as a function of the space coordinates [6, 16]. It
is provided an information how an antenna directs the energy it radiates.
(b) Directivity and Gain
Directivity is referred to as the ratio of radiation to the intensity that would be
obtained if the antenna recognizes the power. Gain means a measure that is
describing the performance of an antenna. However, both are closely related
to each other [12]. Antenna gain is a more important specification than directivity, as it takes in account all the losses and it’s a product of directivity and
efficiency [16]. The efficiency is being measured by losses of the antenna due
to manufacturing faults, resistance and other related factors.
(c) Bandwidth
The term bandwidth is classified as the frequency range in which the outcomes
of the antenna occur according to certain characteristics. It is typically measured
in unit of hertz (Hz) [6]. It is referring to the range of frequencies over which
the antenna can operate correctly.
(d) Return Loss
Return loss is the power which signifies the total power that is lost to the load
and reflect from insertion of a device in the transmission line [6]. Therefore,
the value of return loss is equal to voltage standing wave ratio (VSWR) where
the function is to represent the communication between the transmitter and an
antenna [12].
(e) Voltage Standing Wave Ratio
The voltage standing wave ratio (VSWR) is an indication of the amount of
mismatch between an antenna and the feed line connecting to it. Highest power
transfer between the transmitter and the antenna must carry out for the antenna
to perform effectively [6]. When the impedance of the antenna (Zin) matches
with the transmitter (ZS), it will transfer maximum power. According to [12,
16], the maximum power transfer theorem, it can only be transmitted if the
transmitter impedance is a complex conjugate of the antenna impedance being
S. B. Ismail et al.
be mounted directly above the microstrip line without the need to drill or cut a hole
in the ground plane [3, 10, 14].
13.2.3 Basic Antenna Parameters
A dielectric resonator antenna is characterized by various factors such as high efficiency, compact size, and wide operational bandwidth. To meet the characteristics
or specifications, it needs to refer to several parameters. The basic parameters of an
antenna include the radiation pattern, directivity, gain, bandwidth, return loss, and
voltage standing wave ratio (VSWR) [15].
(a) Radiation Pattern
Radiation pattern is a visual expression of an antenna’s radiation properties.
The radiation pattern is commonly known as a mathematical function of the
antenna’s radiation properties as a function of the space coordinates [6, 16]. It
is provided an information how an antenna directs the energy it radiates.
(b) Directivity and Gain
Directivity is referred to as the ratio of radiation to the intensity that would be
obtained if the antenna recognizes the power. Gain means a measure that is
describing the performance of an antenna. However, both are closely related
to each other [12]. Antenna gain is a more important specification than directivity, as it takes in account all the losses and it’s a product of directivity and
efficiency [16]. The efficiency is being measured by losses of the antenna due
to manufacturing faults, resistance and other related factors.
(c) Bandwidth
The term bandwidth is classified as the frequency range in which the outcomes
of the antenna occur according to certain characteristics. It is typically measured
in unit of hertz (Hz) [6]. It is referring to the range of frequencies over which
the antenna can operate correctly.
(d) Return Loss
Return loss is the power which signifies the total power that is lost to the load
and reflect from insertion of a device in the transmission line [6]. Therefore,
the value of return loss is equal to voltage standing wave ratio (VSWR) where
the function is to represent the communication between the transmitter and an
antenna [12].
(e) Voltage Standing Wave Ratio
The voltage standing wave ratio (VSWR) is an indication of the amount of
mismatch between an antenna and the feed line connecting to it. Highest power
transfer between the transmitter and the antenna must carry out for the antenna
to perform effectively [6]. When the impedance of the antenna (Zin) matches
with the transmitter (ZS), it will transfer maximum power. According to [12,
16], the maximum power transfer theorem, it can only be transmitted if the
transmitter impedance is a complex conjugate of the antenna impedance being